路由的基本使用

create-react-app router_app，创建react项目：router_app。默认使用当前react的最新版本：react@18、react-dom@18。
npm install -save react-router-dom，默认下载安装最新版本r：react-router-dom@6。

涉及的文件包括：

模板文件index.html
入口文件index.js
路由表文件routes/index.jsx
入口组件App.js
路由组件pages/Home/index.jsx，即Home组件
路由组件pages/About/index.jsx，即About组件

在这里插入图片描述

模板文件index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <link rel="stylesheet" href="%PUBLIC_URL%/css/bootstrap.css">
    <title>React App</title>
  </head>
  <body>
    <noscript>You need to enable JavaScript to run this app.</noscript>
    <div id="root"></div>
  </body>
</html>

入口文件index.js

import React from 'react';
import ReactDOM from 'react-dom/client';
import {BrowserRouter} from "react-router-dom";
import App from './App';

const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(
    <BrowserRouter>
        <App />
    </BrowserRouter>
);

routes/index.js

import { Navigate } from "react-router-dom";
import About from "../pages/About";
import Home from "../pages/Home";

const routes = [
    {
        path:"/about",
        element:<About/>
    },
    {
        path:"/home",
        element:<Home/>
    },
    {
        path:"/",
        element:<Navigate to="/about"/>
    }
]

export default routes;

入口组件App.js

import React from 'react'
import {NavLink,useRoutes} from "react-router-dom";
import routes from "./routes";

export default function App() {
  const element = useRoutes(routes);
  return (
    <div>
      <div className="row">
        <div className="col-xs-offset-2 col-xs-8">
          <div className="page-header"><h2>Vue Router Demo</h2></div>
        </div>
      </div>
      <div className="row">
        <div className="col-xs-2 col-xs-offset-2">
          <div className="list-group">
            <NavLink className="list-group-item" to="/about">About</NavLink>
            <NavLink className="list-group-item" to="/home">Home</NavLink>
          </div>
        </div>
        <div className="col-xs-6">
          <div className="panel">
            <div className="panel-body">
            {element}
            </div>
          </div>
        </div>
      </div>
    </div>
  )
}

pages/Home/index.jsx（Home组件）

import React from 'react'

export default function Home() {
  return (
    <h2>我是Home的内容</h2>
  )
}

pages/About/index.jsx（About组件）

import React from 'react'

export default function About() {
  return (
    <h2>我是About的内容</h2>
  )
}

实现嵌套路由

路由结构如下：

/about，About组件
/home，Home组件
- /home/news，News组件
- /home/message，Message组件

在pages文件夹下新建文件夹：News，News下新建文件：index.jsx，即News组件；
在pages文件夹下新建文件夹：Message，Message下新建文件：index.jsx，即Message组件。

代码更新涉及的文件有：

路由表文件routes/index.js
pages/Home/index.jsx，即Home组件
pages/News/index.jsx，即News组件
pages/Message/index.jsx，即Message组件

在这里插入图片描述

routes/index.js

import { Navigate } from "react-router-dom";
import About from "../pages/About";
import Home from "../pages/Home";
import News from "../pages/News";
import Message from "../pages/Message";

const routes = [
    {
        path:"/about",
        element:<About/>
    },
    {
        path:"/home",
        element:<Home/>,
        children:[
            {
                path:"news",
                element:<News/>
            },
            {
                path:"message",
                element:<Message/>
            },
        ]
    },
    {
        path:"/",
        element:<Navigate to="/about"/>
    }
]

export default routes;

用 children 来嵌套路由。

Home/index.jsx

import React from 'react';
import { NavLink,Outlet } from 'react-router-dom';

export default function Home() {
  return (
    <div>
      <h2>Home组件内容</h2>
      <div>
        <ul className="nav nav-tabs">
          <li>
            {/* <NavLink to="/home/news" className="list-group-item">News</NavLink> */}
            {/* <NavLink to="./news" className="list-group-item">News</NavLink> */}
            <NavLink to="news" className="list-group-item">News</NavLink>
          </li>
          <li>
            <NavLink to="/home/message" className="list-group-item">Message</NavLink>
          </li>
        </ul>
        <Outlet/>
      </div>
    </div>
  )
}

路由链接中的 to 属性值，可以是
- to="/home/news"，即全路径
- to="./news"，即相对路径
- to="news"
用 <Outlet/> 指定路由组件的展示位置。

News/index.jsx

import React from 'react'

export default function News() {
    return (
        <ul>
            <li>news001</li>
            <li>news002</li>
            <li>news003</li>
        </ul>
    )
}

Message/index.jsx

import React from 'react'

export default function Message() {
    return (
        <div>
            <ul>
                <li>
                    <a href="/message1">message001</a>&nbsp;&nbsp;
                </li>
                <li>
                    <a href="/message2">message002</a>&nbsp;&nbsp;
                </li>
                <li>
                    <a href="/message/3">message003</a>&nbsp;&nbsp;
                </li>
            </ul>
        </div>
    )
}