<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在Java中，常量是指在程序运行期间不会发生改变的值。Java提供了几种类型的常量，包括字面常量、常量变量和符号常量。下面是一些关于Java常量的示例代码：</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>字面常量</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">字面常量是直接在代码中给出的常量值，例如：</p><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-java" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">int</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">a</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-number" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">10</span>; <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 整型字面常量 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">float</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">b</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-number" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">3.14f</span>; <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 浮点型字面常量 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">boolean</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">c</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-literal" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">true</span>; <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 布尔型字面常量 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">char</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">d</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-string" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: green; line-height: 24px;">'A'</span>; <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 字符型字面常量</span></td></tr></tbody></table></code></pre><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>常量变量</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">常量变量是通过关键字<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">final</code>声明的变量，它只能被赋值一次，例如：</p><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-java" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">final</span> <span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">int</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">e</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-number" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">20</span>; <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 常量变量e的值为20，不能被修改 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">e = <span class="hljs-number" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">30</span>; <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 编译器会报错，因为e是常量变量</span></td></tr></tbody></table></code></pre><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>符号常量</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">符号常量是用关键字<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">static</code>和<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">final</code>声明的常量，它可以在程序的所有实例中被共享，例如：</p><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-java" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">public</span> <span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">class</span> <span class="hljs-title class_" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(0, 127, 170); line-height: 24px;">MyClass</span> {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">public</span> <span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">static</span> <span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">final</span> <span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">int</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">FOO</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-number" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">10</span>; <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 符号常量FOO的值为10，不能被修改 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">}</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在上述代码中，我们定义了一个名为<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">FOO</code>的符号常量，它的值为10。由于它是静态的，因此可以在程序的所有实例中被共享。由于它是final的，因此不能被修改。我们可以通过以下方式使用它：</p><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-java" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">int</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">foo</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> MyClass.FOO; <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 使用符号常量FOO</span></td></tr></tbody></table></code></pre><p><br/></p>
文章列表
<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在Java中定义变量时，需要注意以下几点：</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>变量名：变量名必须符合Java的命名规则，即必须以字母、下划线或美元符号开头，后面可以跟着字母、数字或下划线。变量名是区分大小写的，因此变量<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">age</code>和<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">Age</code>是两个不同的变量。</p></li><li><p>数据类型：在定义变量时，必须指定变量的数据类型。Java支持的数据类型包括整数类型（如int）、浮点类型（如float和double）、字符类型（如char）、布尔类型（如boolean）等。</p></li><li><p>赋值：变量定义后，必须对其进行赋值才能使用。未赋值的变量会被赋予默认值，具体取决于其数据类型。例如，整数类型的变量未赋值时会被赋值为0，布尔类型的变量未赋值时会被赋值为false。</p></li><li><p>声明位置：变量的声明通常放在代码的顶部，也可以放在方法或构造函数的内部。但是，如果变量是局部变量（即定义在方法或构造函数内部），则只能在定义它的方法或构造函数中使用。</p></li><li><p>访问修饰符：Java提供了访问修饰符来控制变量的可见性。public、protected和default（没有修饰符）都可以用来声明类的成员变量，而private可以用来声明私有变量。public和protected变量可以在其所在的类和其他类中访问，default变量可以在其所在的类中访问，而private变量只能在所在的类中访问。</p></li><li><p>作用域：变量的作用域指的是变量的可见性范围。在Java中，变量的作用域可以是局部的或全局的。局部变量是指在方法或构造函数内部定义的变量，只能在其所在的代码块中访问。全局变量是指在类中定义的变量，可以在整个类中访问。</p></li><li><p>初始值：如果定义变量时没有指定初始值，则Java会根据变量的类型自动为其赋一个初始值。例如，整数类型的变量会被赋值为0，布尔类型的变量会被赋值为false，字符类型的变量会被赋值为null字符，浮点类型的变量会被赋值为0.0。</p></li></ol><p><br/></p>
<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">以下是一个简单的Java程序，演示了变量的定义和使用：</p><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-java" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">public</span> <span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">class</span> <span class="hljs-title class_" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(0, 127, 170); line-height: 24px;">MyProgram</span> {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">public</span> <span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">static</span> <span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">void</span> <span class="hljs-title function_" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(0, 127, 170); line-height: 24px;">main</span><span class="hljs-params" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">(String[] args)</span> {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 定义整数类型的变量 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">int</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">myInt</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-number" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">10</span>;</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><br/></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 定义浮点类型的变量 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">float</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">myFloat</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-number" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">3.14f</span>;</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><br/></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 定义布尔类型的变量 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">boolean</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">myBool</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-literal" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">true</span>;</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><br/></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 定义字符类型的变量 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">char</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">myChar</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-string" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: green; line-height: 24px;">'A'</span>;</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><br/></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 定义双精度浮点类型的变量 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">double</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">myDouble</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-number" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">2.5</span>;</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><br/></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 打印变量的值 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">System.out.println(<span class="hljs-string" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: green; line-height: 24px;">"myInt = "</span> + myInt);</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">System.out.println(<span class="hljs-string" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: green; line-height: 24px;">"myFloat = "</span> + myFloat);</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">System.out.println(<span class="hljs-string" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: green; line-height: 24px;">"myBool = "</span> + myBool);</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">System.out.println(<span class="hljs-string" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: green; line-height: 24px;">"myChar = "</span> + myChar);</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">System.out.println(<span class="hljs-string" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: green; line-height: 24px;">"myDouble = "</span> + myDouble);</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">}</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">}</td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在上述代码中，我们定义了五个不同类型的变量：整数类型（int）、浮点类型（float）、布尔类型（boolean）、字符类型（char）和双精度浮点类型（double）。每个变量都有一个名称（例如myInt、myFloat等）和一个类型（例如int、float等），并且每个变量都有一个初始值。在本例中，我们为每个变量赋了一个初始值，然后使用System.out.println()语句将它们的值打印到控制台上。输出结果如下：</p><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">myInt = 10</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">myFloat = 3.14</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">myBool = true</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">myChar = A</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">myDouble = 2.5</td></tr></tbody></table></code></pre><p><br/></p>
<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">Java是一种强类型语言，每个变量都必须先定义其数据类型。Java的数据类型可以分为两类：基本数据类型和引用数据类型。</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>基本数据类型</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">基本数据类型是Java语言中预先定义好的数据类型，包括以下几种：</p><ul style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>整型（int）：用于表示整数，取值范围为-2147483648到2147483647。</p></li><li><p>短整型（short）：用于表示短整数，取值范围为-32768到32767。</p></li><li><p>长整型（long）：用于表示长整数，取值范围为-9223372036854775808到9223372036854775807。</p></li><li><p>字符型（char）：用于表示一个字符，取值范围为'\u0000'到'\uffff'。</p></li><li><p>布尔型（boolean）：用于表示真或假，只能取true或false两个值。</p></li><li><p>浮点型（float）：用于表示单精度浮点数，取值范围为1.4E-45到3.4E+38。</p></li><li><p>双精度浮点型（double）：用于表示双精度浮点数，取值范围为2.2E-308到1.8E+308。</p></li></ul><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">除了以上几种基本数据类型外，Java还提供了其他几种数据类型，如定点数类型（BigDecimal）和日期时间类型（java.util.Date、java.time.LocalDate等），但这些类型通常在实际开发中使用的较少。</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>引用数据类型</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">引用数据类型是Java语言中自定义的数据类型，包括类、接口和数组等。这些类型可以用来封装复杂的数据结构，并且可以定义自己的属性和方法。引用数据类型和基本数据类型不同，它们是通过引用传递的，而不是通过值传递的。这意味着当一个引用类型的变量被传递给一个方法时，方法可以修改该变量引用的对象的状态，但不能直接修改该变量的值。</p><p><br/></p>
<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在计算机科学中，二进制是一种数值表示法，它使用二个符号（0和1）来表示数值。在Java编程语言中，二进制扮演重要角色，因为它被广泛用于计算机内部以高效地存储和操作数据。</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>二进制在Java中的表示：</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在Java中，二进制数通常以0b或0B开始，后跟一串由0和1组成的数字序列。例如，<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">0b1010</code>表示一个二进制数，其值为10（在十进制中）。</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>二进制字面量在Java中的使用：</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">Java 7引入了二进制字面量，这是一种新的数值表示法，允许开发者使用二进制格式表示数值。这种字面量的使用非常方便，尤其是对于需要处理大量二进制数据的开发者来说。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">例如，要表示十进制数22，你可以使用二进制字面量<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">0b0010110</code>。Java编译器会将其转换为十进制数22。</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>二进制在位操作中的使用：</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在Java中，二进制被广泛用于位操作。位操作是一种直接在二进制位上执行的操作，如按位与(&)、按位或(|)、按位异或(^)、按位取反(~)等。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">例如，假设我们有一个整数变量<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">a</code>，其值为5（在二进制中为<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">0101</code>）。如果我们想要将该变量与另一个整数变量<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">b</code>（在二进制中为<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">1010</code>）进行按位与操作，那么结果将是<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">0000</code>（在十进制中为0）。</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>二进制的逻辑运算：</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在Java中，逻辑运算符（&&、||、!）可用于执行逻辑运算。这些运算符在处理布尔值（true或false）时非常有用。例如，<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">(a > b) && (a != c)</code>将检查两个条件是否同时为真。</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>二进制在数据传输中的使用：</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在计算机通信中，二进制被广泛用于数据传输。因为二进制数据的处理和传输效率比其他数据格式更高。在网络通信中，数据通常以二进制格式发送，以确保快速和可靠的数据传输。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">总之，二进制在Java编程中扮演着重要角色，它被广泛用于数值表示、位操作、逻辑运算和数据传输等方面。了解并掌握二进制的概念和应用有助于提高开发者的编程技能和效率。</p><p><br/></p>
<ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>转义符（Escape Character）：</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在Java编程语言中，转义符是一种特殊的字符序列，它用于表示不能直接输入的字符。转义符通常以反斜杠（\）开头，后跟一个或多个字符。例如，<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">\n</code>表示换行符，<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">\t</code>表示制表符。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">以下是一些常见的Java转义符：</p><ul style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">\n</code>：换行符（New Line）</p></li><li><p><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">\t</code>：制表符（Tab）</p></li><li><p><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">\"</code>：双引号（"）</p></li><li><p><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">\'</code>：单引号（'）</p></li><li><p><code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">\\</code>：反斜杠（\）</p></li></ul><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">此外，Java还提供了其他一些转义符，如<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">\b</code>（退格符）、<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">\r</code>（回车符）和<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">\f</code>（换页符）等。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">示例：</p><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-java" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><p><span class="code-lang" style="box-sizing: border-box; padding: 0px 0px 0px 14px; -webkit-font-smoothing: antialiased; list-style: none; font-family: PingFangSC-Semibold; margin: 0px; color: rgb(18, 6, 73); flex: 1 0 auto; font-size: 16px; font-weight: 600; letter-spacing: 0px; text-align: justify;">java</span><span class="code-copy" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: PingFangSC-Regular; margin: 0px; align-items: center; color: rgb(120, 134, 164); display: flex; font-size: 13px; letter-spacing: 0px; line-height: 14px; text-align: justify; user-select: none;"><span class="code-copy-text" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji" !important; margin: 0px 20px 0px 7px;">复制代码</span></span></p><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">System.out.println(<span class="hljs-string" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: green; line-height: 24px;">"Hello\nWorld"</span>); <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 输出两行：Hello和World </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">System.out.println(<span class="hljs-string" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: green; line-height: 24px;">"\"Hello World\""</span>); <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 输出一行："Hello World"</span></td></tr></tbody></table></code></pre><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>注释（Comment）：</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">注释是用于解释代码的文本，不会被编译器执行。Java中有两种注释：单行注释和多行注释。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">（1）单行注释：以双斜杠（//）开头，该行剩余部分都被视为注释。例如：</p><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-java" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 这是一个单行注释 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">int</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">x</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-number" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">5</span>; <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 变量x的初始值为5</span></td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">（2）多行注释：以/<em style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px;">开头，以</em>/结尾，中间的所有内容都被视为注释。例如：</p><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-java" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">/* </span></span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">这是一个多行注释 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">下面是一个for循环 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">*/</span> </td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">for</span> (<span class="hljs-type" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">int</span> <span class="hljs-variable" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">i</span> <span class="hljs-operator" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">=</span> <span class="hljs-number" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">0</span>; i < <span class="hljs-number" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">10</span>; i++) {</td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">System.out.println(i); <span class="hljs-comment" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(105, 105, 105); line-height: 24px;">// 输出0到9的数字 </span></td></tr><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">}</td></tr></tbody></table></code></pre><p><br/></p>
<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">使用IntelliJ IDEA编写Java程序需要以下步骤：</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>安装并启动IntelliJ IDEA：从JetBrains官方网站下载并安装IntelliJ IDEA，然后启动它。</p></li><li><p>创建Java项目：在IntelliJ IDEA中，选择"File"（文件）菜单，然后选择"New"（新建）> "Project"（项目）。在弹出的窗口中，选择"Java"并设置项目名称和位置。</p></li><li><p>创建Java类：在项目视图中，右键单击"src"目录并选择"New"（新建）> "Java Class"（Java类）。输入类的名称并点击"OK"。</p></li><li><p>编写Java代码：在Java类中，可以开始编写Java代码。可以使用自动补全和代码提示来加快编码速度。</p></li><li><p>运行Java程序：在代码编辑器中，点击"Run"（运行）按钮或使用快捷键"Shift+F10"来运行程序。输出结果将在控制台中显示。</p></li><li><p>调试Java程序：可以使用IntelliJ IDEA的调试功能来调试Java程序。在代码编辑器中设置断点，然后单击"Debug"（调试）按钮或使用快捷键"Shift+F9"来启动调试器。</p></li><li><p>管理和导入依赖项：如果Java项目使用外部库或框架，可以使用IntelliJ IDEA的依赖项管理工具来导入和管理这些依赖项。在项目视图中，右键单击项目根目录并选择"Open Module Settings"（打开模块设置）> "Libraries"（库）来管理和添加依赖项。</p></li><li><p>版本控制：IntelliJ IDEA支持流行的版本控制系统，如Git和SVN。可以使用内置的版本控制工具来管理代码版本和进行团队协作。</p></li><li><p>插件和工具：IntelliJ IDEA具有丰富的插件和工具生态系统，可以根据需要扩展其功能。可以从"File"（文件）菜单下的"Settings"（设置）> "Plugins"（插件）页面中搜索和安装插件。</p></li><li><p>学习和掌握快捷键和常用快捷键可以帮助提高编码效率。可以在"Help"（帮助）菜单下的"Keyboard Shortcuts"（键盘快捷键）页面中查看所有可用快捷键。</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">以上是使用IntelliJ IDEA编写Java程序的基本步骤。除了这些基本操作外，IntelliJ IDEA还提供了许多高级特性和工具，可以帮助开发者更高效地进行编码、调试和管理项目。</p><p><br/></p>
<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">Java程序中的main方法是程序的入口点，是程序执行的起点。当Java程序运行时，JVM（Java虚拟机）会查找具有main方法的类，并从该类中的main方法开始执行程序。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">main方法的标准签名如下：</p><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin-top: 14px; margin-bottom: 0px; font-size: 15px; overflow: auto; border-radius: 6px; color: rgb(5, 7, 59);"><code class="language-java" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px; font-size: 1em; tab-size: 4;"><table class="hljs hljs-ln"><tbody style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><tr style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;" class="firstRow"><td class="hljs-ln-line hljs-ln-numbers" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px; color: rgb(190, 191, 208); letter-spacing: 0px; max-width: 50px; overflow: hidden; text-align: justify; user-select: none; vertical-align: top; white-space-collapse: collapse;" width="30"><br/></td><td class="hljs-ln-line hljs-ln-code" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">public</span> <span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">static</span> <span class="hljs-keyword" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(121, 40, 161); line-height: 24px;">void</span> <span class="hljs-title function_" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(0, 127, 170); line-height: 24px;">main</span><span class="hljs-params" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(170, 93, 0); line-height: 24px;">(String[] args)</span></td></tr></tbody></table></code></pre><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">其中，参数<code class=" inline" style="box-sizing: border-box; padding: 1px 4px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; margin: 0px 2px; font-size: 12.75px; tab-size: 4; background-color: rgba(27, 31, 35, 0.05); border-radius: 3px;">args</code>是一个字符串数组，用于接收从命令行传递给程序的参数。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在main方法中，可以编写程序的主要逻辑代码，包括创建对象、调用方法等操作。当程序执行完毕时，main方法返回。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">需要注意的是，只有包含main方法的类才能作为Java程序的入口点。此外，main方法必须是public和static的，这样JVM才能访问和执行它。</p><p><br/></p>
<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">Node.js的事件循环是其非阻塞I/O操作的基础，也是其能处理大量并发操作的重要因素。事件循环是Node.js运行机制的核心，它使得Node.js可以异步地处理I/O和CPU操作。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">以下是Node.js事件循环的详细介绍：</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p><span style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji" !important; margin: 0px; font-weight: 700;">调用栈（Call Stack）</span>：在任何时候，Node.js都只有一条线程运行，并且会持续执行调用栈中的任务。调用栈中的任务可以是JavaScript代码，也可以是系统V8引擎的回调函数。</p></li><li><p><span style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji" !important; margin: 0px; font-weight: 700;">事件队列（Event Queue）</span>：当一个异步事件完成（如一个I/O操作）时，它就会被添加到事件队列中。例如，一个HTTP请求完成时，就会产生一个事件并添加到事件队列中。</p></li><li><p><span style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji" !important; margin: 0px; font-weight: 700;">事件循环（Event Loop）</span>：事件循环的工作就是持续地检查调用栈是否为空，如果为空，就从事件队列中取出一个事件放到调用栈中执行。这样，只要有异步事件完成，就会被执行，实现了非阻塞的I/O操作。</p></li><li><p><span style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji" !important; margin: 0px; font-weight: 700;">微任务（Microtasks）和宏任务（Macrotasks）</span>：在事件循环中，有两种类型的任务：微任务和宏任务。宏任务包括：脚本整体（整体代码script）、setTimeout、setInterval、setImmediate、I/O、UI渲染等。微任务包括：Promise.then/catch/finally、MutationObserver等。当事件循环开始时，它首先会查看微任务队列是否为空，如果微任务队列不为空，就会先执行所有的微任务，然后再执行一个宏任务。在执行宏任务的过程中，如果有微任务被添加到微任务队列中，那么在当前的宏任务结束后，就会立即执行所有的微任务，然后再取出下一个宏任务执行。</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">这个机制确保了只要有一个宏任务在执行，微任务就会全部执行完。但是请注意，如果在执行宏任务的过程中，有新的宏任务被添加到了宏任务队列中，那么这个新的宏任务将会被推后到当前宏任务执行完后再执行。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">以上就是Node.js的事件循环机制。它允许Node.js在单线程中处理大量的并发操作，使得Node.js在处理I/O密集型任务时能高效运行。</p><p><br/></p>
<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在Node.js中，事件循环是其非阻塞I/O操作的基础，也是其能处理大量并发操作的重要因素。以下是混合嵌套事件循环的案例介绍：</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">假设我们有一个异步的HTTP请求，需要等待一个外部API的响应。在这个等待期间，我们希望Node.js能够处理其他的任务，例如响应其他的HTTP请求。这就需要使用到事件循环机制。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在Node.js中，事件循环的基本流程如下：</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>创建一个新的HTTP请求。</p></li><li><p>将请求添加到任务队列中。</p></li><li><p>开始执行事件循环。</p></li><li><p>执行当前的任务（这里是HTTP请求）。</p></li><li><p>如果任务队列不为空，继续执行队列中的下一个任务。</p></li><li><p>如果任务队列为空，就等待新的任务添加到队列中。</p></li><li><p>如果有新的任务添加到队列中，就继续执行这个任务。</p></li><li><p>重复步骤4-7，直到所有的任务都执行完毕。</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在这个过程中，如果有一个任务需要等待外部操作（例如HTTP请求），那么它就会被添加到等待队列中，然后事件循环会继续执行其他的任务。当外部操作完成后，一个事件会被添加到事件队列中，然后事件循环会回到等待队列中取出这个任务，并执行它。这就是事件循环的基本原理。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">现在我们来看一个混合嵌套的例子。假设我们有一个HTTP服务器，需要处理来自客户端的多个请求。同时，我们也需要定期从一个外部API获取数据。这就可以使用事件循环来实现：</p><ol style="box-sizing: border-box; padding: 0px 0px 0px 32px; -webkit-font-smoothing: antialiased; list-style-position: outside; list-style-image: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 1em; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;" class=" list-paddingleft-2"><li><p>创建一个HTTP服务器，监听客户端的请求。</p></li><li><p>当有新的请求到达时，创建一个新的HTTP请求，并将它添加到任务队列中。</p></li><li><p>开始执行事件循环。</p></li><li><p>执行当前的任务（这里是HTTP请求）。</p></li><li><p>如果任务队列不为空，继续执行队列中的下一个任务。如果下一个任务是一个HTTP请求，就取出这个请求并执行它。如果下一个任务是获取外部API的数据，就将这个任务添加到等待队列中。</p></li><li><p>如果任务队列为空，而且等待队列也不为空，就从等待队列中取出一个任务并执行它。如果等待队列也为空，就等待新的任务添加到队列中。</p></li><li><p>如果有新的任务添加到队列中，就继续执行这个任务。</p></li><li><p>重复步骤4-7，直到所有的任务都执行完毕。</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", "Microsoft YaHei", "Source Han Sans CN", sans-serif, "Apple Color Emoji", "Segoe UI Emoji"; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在这个例子中，我们使用了事件循环的特性来同时处理多个HTTP请求和定期获取外部API的数据。这就是混合嵌套事件循环的一个例子。</p><p><br/></p>