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<p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React脚手架(create-react-app)是一种流行的前端开发框架,它提供了一种快速构建React应用程序的开发环境。通过使用脚手架,开发者可以更容易地创建、开发和部署React应用程序。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">首先,React脚手架提供了一个完整的开发环境,包括Node.js、npm、Yarn等必要的工具和库。它还提供了构建工具(如Webpack)和代码编辑器(如Visual Studio Code)等开发工具,使得开发者可以更高效地进行开发。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">其次,React脚手架提供了一个可扩展的应用程序模板,包括基本的目录结构、代码库和配置文件等。开发者可以根据自己的需求进行定制和扩展,以满足应用程序的实际需求。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">此外,React脚手架还提供了一些内置的插件和工具,用于支持React特性和开发流程。例如,它支持热模块替换(HMR)技术,可以在开发过程中自动更新页面而无需重新加载整个页面。它还支持React路由、状态管理、Redux等常用的React特性和工具。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">最后,React脚手架还提供了可扩展性,允许开发者在脚手架的基础上添加自己的工具和库。例如,开发者可以使用脚手架提供的Webpack配置文件进行自定义配置,以满足特定的构建需求。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React脚手架提供了一种快速、高效且可扩展的前端开发环境,使得开发者可以更容易地创建、开发和部署React应用程序。它内置了许多常用的工具和库,同时也支持自定义和扩展,以满足不同应用程序的需求。</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React虚拟DOM是一个抽象的树形结构,它通过与实际DOM进行对比,从而决定哪些节点需要更新。在React中,使用虚拟DOM的目的是为了减少不必要的DOM操作,从而提高应用程序的性能。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">DOM diff算法是React中用于比较虚拟DOM和实际DOM之间差异的算法。通过这个算法,React可以确定哪些节点需要更新,哪些节点需要保留,以及哪些节点需要新建。这个算法的主要思想是通过对两个树进行深度优先遍历来比较它们的差异,从而找到需要更新的部分。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React中,diff算法的执行过程如下:</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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>首先,React会比较两个树的根节点。如果它们的类型(比如一个是div,另一个是span)或者属性不同,那么React就会销毁旧的树并新建一棵新的树。</p></li><li><p>如果两个树的类型和属性都相同,那么React就会保留旧的树,并只更新需要改变的部分。这个过程会一直递归地向下进行,直到找到需要更新的具体节点。</p></li><li><p>在找到需要更新的节点后,React会使用具体的DOM操作(比如appendChild、removeChild、innerHTML等)来更新DOM。</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在执行diff算法时,React会考虑以下几个因素:</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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>节点的类型和属性;</p></li><li><p>节点的位置(比如它的父节点是谁,它在兄弟节点中的位置等);</p></li><li><p>数据的变化(比如一个列表中的项增加了或减少了)。</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">通过这种方式,React可以有效地减少不必要的DOM操作,从而提高应用程序的性能。同时,React还提供了开发者工具,使得开发者可以更方便地调试和优化应用程序的性能。</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React组件的生命周期是指从组件被创建、使用到被销毁的整个过程。在这个过程中,React提供了自动执行的钩子函数,我们称之为生命周期函数。这些生命周期函数可以帮助我们更好地管理和控制组件的行为。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React中,组件的生命周期大致可以分为三个阶段:组件挂载阶段、组件更新阶段和组件销毁卸载阶段。</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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 class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin-top: 0px; margin-bottom: 0px; line-height: 1.75;">挂载阶段:在组件挂载阶段,React会调用以下生命周期函数:</p></li><ul style="list-style-type: disc;" class=" list-paddingleft-2"><li><p>constructor:在组件创建之前被调用一次,用于初始化组件的状态和绑定事件处理函数。</p></li><li><p>componentDidMount:组件完成挂载后被调用,此时组件已经显示在页面上。这个方法通常用于执行一些只需要在组件挂载时执行一次的操作,如获取数据、订阅事件等。</p></li></ul><li><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin-top: 0px; margin-bottom: 0px; line-height: 1.75;">更新阶段:当组件的state或props发生变化时,React会重新渲染组件并调用以下生命周期函数:</p></li><ul style="list-style-type: disc;" class=" list-paddingleft-2"><li><p>getDerivedStateFromProps:在调用render方法之前被调用,用于根据传入的props派生出新的state。</p></li><li><p>render:组件的render方法根据state和props生成虚拟DOM。</p></li><li><p>componentDidUpdate:组件更新完成后被调用,此时组件已经更新并重新渲染完成。这个方法通常用于执行一些只需要在组件更新时执行一次的操作,如重新获取数据、重新订阅事件等。</p></li></ul><li><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin-top: 0px; margin-bottom: 0px; line-height: 1.75;">销毁卸载阶段:当组件被销毁时,React会调用以下生命周期函数:</p></li><ul style="list-style-type: disc;" class=" list-paddingleft-2"><li><p>componentWillUnmount:组件即将被销毁时被调用,用于执行一些需要在组件销毁前完成的操作,如取消订阅事件、清理资源等。</p></li></ul></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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React组件的生命周期及其中的主要生命周期函数。通过合理利用这些生命周期函数,我们可以更好地管理组件的状态和行为,提高应用程序的性能和可维护性。</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React组件的生命周期是指组件从创建、更新到销毁的整个过程。在这个过程中,React提供了多个生命周期函数,可以帮助我们更好地管理和控制组件的行为。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React中,组件的生命周期大致可以分为三个阶段:挂载阶段、更新阶段和销毁阶段。</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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>挂载阶段:当组件被创建并添加到DOM中时,会依次执行以下生命周期函数:</p></li></ol><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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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>constructor:在类组件中,这是构造函数,用于初始化组件的状态和绑定事件处理函数。通常用于初始化state和绑定事件处理函数。</p></li><li><p>componentDidMount:组件完成挂载后被调用,此时组件已经显示在页面上。这个方法通常用于执行一些只需要在组件挂载时执行一次的操作,如获取数据、订阅事件等。</p></li></ul><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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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>更新阶段:当组件的state或props发生变化时,React会重新渲染组件并执行以下生命周期函数:</p></li></ol><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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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>getDerivedStateFromProps:在调用render方法之前被调用,用于根据传入的props派生出新的state。</p></li><li><p>render:组件的render方法根据state和props生成虚拟DOM。</p></li><li><p>componentDidUpdate:组件更新完成后被调用,此时组件已经更新并重新渲染完成。这个方法通常用于执行一些只需要在组件更新时执行一次的操作,如重新获取数据、重新订阅事件等。</p></li></ul><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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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>销毁阶段:当组件被销毁时,React会调用以下生命周期函数:</p></li></ol><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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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>componentWillUnmount:组件即将被销毁时被调用,用于执行一些需要在组件销毁前完成的操作,如取消订阅事件、清理资源等。</p></li></ul><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">除了上述标准的生命周期函数之外,React还提供了其他一些生命周期方法,如getSnapshotBeforeUpdate和componentDidMount等。这些方法可以帮助我们更详细地控制组件的行为和性能。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">通过合理利用React提供的生命周期函数,我们可以更好地管理组件的状态和行为,提高应用程序的性能和可维护性。</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在React中,可以通过使用受控组件和非受控组件来收集表单数据。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">对于受控组件,可以通过将表单的输入元素与组件的state进行绑定,然后使用onChange事件处理函数来更新state。当用户在输入框中输入文本时,onChange事件处理函数会被触发,从而更新state中的值。例如:</p><pre style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, &quot;Liberation Mono&quot;, 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-jsx" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: SFMono-Regular, Consolas, &quot;Liberation Mono&quot;, 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;">import</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;">React</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;">Component</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;">from</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;">&#39;react&#39;</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-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;">Form</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;">extends</span> <span class="hljs-title class_ inherited__" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(0, 127, 170); line-height: 24px;">Component</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-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;">constructor</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;">props</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-variable language_" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">super</span>(props);</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-variable language_" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">this</span>.<span class="hljs-property" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">state</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-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">username</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;">&#39;&#39;</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-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">password</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;">&#39;&#39;</span> &nbsp;</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><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;">handleSubmit = <span class="hljs-function" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">(<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;">event</span>) =&gt;</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;">event.<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;">preventDefault</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;">const</span> username = <span class="hljs-variable language_" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">this</span>.<span class="hljs-property" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">state</span>.<span class="hljs-property" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">username</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;">const</span> password = <span class="hljs-variable language_" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">this</span>.<span class="hljs-property" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">state</span>.<span class="hljs-property" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">password</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-variable language_" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">console</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;">log</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;">&#39;Username:&#39;</span>, username);</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-variable language_" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">console</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;">log</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;">&#39;Password:&#39;</span>, password);</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;"><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;">handleChange = <span class="hljs-function" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">(<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;">event</span>) =&gt;</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;">const</span> { name, value } = event;</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-variable language_" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">this</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;">setState</span>({ [name]: value });</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;"><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-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;">render</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;"></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;">return</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="language-xml" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;"><span class="hljs-tag" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">&lt;<span class="hljs-name" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">form</span> <span class="hljs-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">onSubmit</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;">{this.handleSubmit}</span>&gt;</span> &nbsp;</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-tag" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">&lt;<span class="hljs-name" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">input</span> <span class="hljs-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">type</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;">&quot;text&quot;</span> <span class="hljs-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">name</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;">&quot;username&quot;</span> <span class="hljs-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">value</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;">{this.state.username}</span> <span class="hljs-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">onChange</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;">{this.handleChange}</span> /&gt;</span> &nbsp;</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-tag" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">&lt;<span class="hljs-name" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">input</span> <span class="hljs-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">type</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;">&quot;password&quot;</span> <span class="hljs-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">name</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;">&quot;password&quot;</span> <span class="hljs-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">value</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;">{this.state.password}</span> <span class="hljs-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">onChange</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;">{this.handleChange}</span> /&gt;</span> &nbsp;</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-tag" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">&lt;<span class="hljs-name" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">button</span> <span class="hljs-attr" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">type</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;">&quot;submit&quot;</span>&gt;</span>Submit<span class="hljs-tag" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">&lt;/<span class="hljs-name" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">button</span>&gt;</span> &nbsp;</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-tag" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; color: rgb(217, 30, 24); line-height: 24px;">&lt;/<span class="hljs-name" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; margin: 0px; line-height: 24px;">form</span>&gt;</span> &nbsp;</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><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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在上面的例子中,我们将表单的输入元素与组件的state中的username和password进行了绑定。当用户在输入框中输入文本时,handleChange函数会被触发,从而更新state中的值。在handleSubmit函数中,我们可以通过this.state来获取表单中的数据。</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React组件组合使用可以带来很多优势,包括提高代码复用性、易于维护和测试、更好的性能等。下面是对React组件组合使用的一些总结:</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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>组合优于继承:在React中,组件之间可以通过组合的方式来实现复杂的交互和UI界面。相比于基于继承的扩展方式,组合更加灵活、可维护,并且可以提高代码的可重用性。</p></li><li><p>父子组件通信:在组合使用组件时,需要确保父子组件之间的通信畅通。可以使用props来传递数据和事件处理函数,或者使用React提供的context来共享数据。</p></li><li><p>组件封装和解耦:通过封装组件可以将复杂的逻辑和UI分离,提高代码的可读性和可维护性。同时,解耦可以降低组件之间的依赖关系,使其更加独立和可重用。</p></li><li><p>组件生命周期:React提供了生命周期函数来控制组件的生命周期。可以使用这些函数来执行一些特定的操作,如数据获取、状态更新等。</p></li><li><p>组件测试和调试:组合使用组件时,需要确保每个组件的功能正常,并且组合后的整体功能也正常。可以使用React提供的测试工具和方法来进行单元测试、集成测试和功能测试。</p></li><li><p>性能优化:通过优化组件的性能,可以提高整个应用程序的性能。可以使用React提供的优化方法,如避免不必要的重新渲染、使用虚拟滚动等。</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React组件组合使用可以提高代码的可维护性、可重用性和性能,同时也可以降低开发和维护的成本。在实际开发中,需要根据具体的场景和需求来选择合适的组合方式,并注意优化组件的性能。</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React组件组合使用可以通过以下步骤进行初始化显示:</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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>创建组件:首先需要创建要使用的组件,可以使用函数组件或类组件的方式。</p></li><li><p>渲染组件:在父组件中,使用React提供的createElement函数将组件渲染到虚拟DOM中。</p></li><li><p>传递props:可以通过父组件传递props给子组件,从而控制子组件的显示和行为。</p></li><li><p>渲染虚拟DOM:React会根据虚拟DOM和实际DOM的差异进行最小化的DOM操作,从而更新页面显示。</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在初始化显示时,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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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>组件的初始状态设置:在组件的构造函数中,需要设置初始的state状态,从而控制组件的显示和行为。</p></li><li><p>props的传递:可以通过父组件传递props给子组件,从而控制子组件的显示和行为。在子组件中,可以通过this.props来获取传递的props。</p></li><li><p>虚拟DOM的渲染:React会根据虚拟DOM和实际DOM的差异进行最小化的DOM操作,从而更新页面显示。在组件更新时,需要使用React提供的setState方法来更新state,并重新渲染虚拟DOM。</p></li></ol><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React组件组合使用可以提高代码的可维护性和可重用性,同时也可以降低开发和维护的成本。在初始化显示时,需要注意组件的初始状态设置、props的传递和虚拟DOM的渲染。</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React组件的三大属性包括props、state和refs。其中,refs是React组件的一个特殊属性,它允许我们访问DOM元素或React元素(虚拟的DOM元素)。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">Refs有两种定义形式:一种是通过React.createRef()来创建,另一种是通过React.forwardRef()来创建。通过React.createRef()创建的refs可以用来访问DOM元素或React元素(虚拟的DOM元素),而通过React.forwardRef()创建的refs则可以用来访问React元素(虚拟的DOM元素)和组件实例。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在事件处理方面,React组件的事件处理函数是通过props传递给子组件的。当事件发生时,子组件会调用相应的事件处理函数,并传递事件对象作为参数。在父组件中,可以通过调用子组件传递的事件处理函数来处理事件。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">同时,refs也可以用来传递事件处理函数。通过将事件处理函数绑定到refs上,可以实现在子组件中触发事件时,父组件能够接收到事件并进行处理。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">refs和事件处理是React组件中非常重要的两个属性。通过refs可以访问DOM元素或React元素(虚拟的DOM元素),并通过事件处理函数来处理事件。同时,refs也可以用来传递事件处理函数,使得父组件和子组件之间的交互更加灵活和方便。</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React组件的props(属性)是一种重要的属性,它用于从组件外部传递数据给组件内部。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">每个组件对象都会有props属性,组件标签的所有属性都保存在props中。这些属性可以是任何有效的JavaScript数据类型,包括字符串、数字、布尔值、对象、数组等。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在父组件中,可以通过传递属性给子组件来传递数据。子组件可以通过this.props来访问这些属性值。注意,在React中,子组件不能修改props的值,只能通过事件处理函数来向父组件传递数据。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">props还可以用来传递事件处理函数。当子组件需要触发事件时,可以通过调用父组件传递的事件处理函数来实现。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">另外,React还提供了对props的校验功能。通过在组件类中使用static propTypes = {...}来定义props的类型和必要性,可以在开发阶段发现和警告不正确的props使用。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">props是React组件中非常重要的属性之一,它用于从外部传递数据给组件内部,并且还可以用来传递事件处理函数。在使用props时,需要注意不能修改其值,只能通过事件处理函数来向父组件传递数据。同时,使用static propTypes = {...}可以校验props的类型和必要性,提高代码的可维护性和可读性。</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, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 0px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">React组件的state是React组件内部的数据源,用于描述组件的状态。当组件的状态发生变化时,React会自动重新渲染组件,并将新的状态传递给组件的render方法,从而更新组件的UI。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">每个React组件都具有一个私有的state属性,这个属性只能在组件内部使用,而不能直接修改。通过调用this.setState方法来更新state,setState接收一个对象,其中包含要更新的属性及其新值。React会自动合并这些变化,并只重新渲染需要更新的部分。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">在state中,可以存储简单的数据类型和复杂的对象、数组等数据结构。这使得开发者能够更灵活地控制组件的状态,提高组件的复用性和可维护性。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; 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,state应该始终视为只读属性。组件只能通过调用setState方法来更新它,而不能直接更改它的值。直接更改state属性的值可能会导致不可预期的结果,因为React可能会在其内部使用异步方式更新状态。</p><p class="" style="box-sizing: border-box; padding: 0px; -webkit-font-smoothing: antialiased; list-style: none; font-family: -apple-system, BlinkMacSystemFont, &quot;Segoe UI&quot;, Roboto, Ubuntu, &quot;Helvetica Neue&quot;, Helvetica, Arial, &quot;PingFang SC&quot;, &quot;Hiragino Sans GB&quot;, &quot;Microsoft YaHei UI&quot;, &quot;Microsoft YaHei&quot;, &quot;Source Han Sans CN&quot;, sans-serif, &quot;Apple Color Emoji&quot;, &quot;Segoe UI Emoji&quot;; margin-top: 14px; margin-bottom: 0px; font-size: 15px; line-height: 1.75; color: rgb(5, 7, 59); text-wrap: wrap;">另外,React中的state属性不仅可以存储简单的数据类型,还可以存储对象和数组等复杂数据类型。这使得开发者能够更灵活地控制组件的状态,提高组件的复用性和可维护性。</p><p><br/></p>