React-Router 4.0入门整理（web方向）

参考REACT ROUTER官方文档 https://reacttraining.com/react-router/

新的React-Router相比于之前的有很大变化，主要思想为一切皆组件，路由也是个组件，react-router是核心，下面分为react-router-dom对应web页面开发，react-router-native对应native应用开发。

React-Router共有三类组件

路由容器组件: 包含 <BrowserRouter>和<HashRouter>
如果你有对应的请求服务器，建议使用 <BrowserRouter>，如果只是一个静态服务器，则使用<HashRouter>

import { BrowserRouter } from "react-router-dom";
ReactDOM.render(
  <BrowserRouter>
    <App />
  </BrowserRouter>,
  holder
);

路由匹配组件: 包含<Route>和<Switch>
<Switch>组件是包裹着<Router>容器，一旦匹配到就停止往下继续匹配
<Route>即路由组件，常见有两种应用 component和Render

<Switch>
    <Routeexactpath="/"component={Home}/>
    <Routepath="/about"component={About}/>
    <Routepath="/contact"render={()=><div>contact</div>}
</Switch>

路由导航组件: 包含<Link>和<NavLink>
<NavLink>是<Link>的封装，增加了激活状态下样式接口

<Link to="/">Home</Link>
// <a href='/'>Home</a>

<NavLink to="/react" activeClassName="hurray">
  React
</NavLink>
// <a href='/react' className='hurray'>React</a>

基本应用参考:

import React from "react";
import { BrowserRouter as Router, Route, Link } from "react-router-dom";

function BasicExample() {
  return (
    <Router>
      <div>
        <ul>
          <li><Link to="/">Home</Link></li>
          <li><Link to="/about">About</Link></li>
          <li> <Link to="/topics">Topics</Link></li>
        </ul>
        <hr />
        <Route exact path="/" component={Home} />
        <Route path="/about" component={About} />
        <Route path="/topics" component={Topics} />
      </div>
    </Router>
  );
}

function Home() {
  return (
    <div>Home</div>
  );
}

function About() {
  return (
    <div>About</div>
  );
}

function Topics({ match }) {
  return (
    <div>
      <h2>Topics</h2>
      <ul>
        <li>
          <Link to={`${match.url}/rendering`}>Rendering with React</Link>
        </li>
        <li>
          <Link to={`${match.url}/components`}>Components</Link>
        </li>
        <li>
          <Link to={`${match.url}/props-v-state`}>Props v. State</Link>
        </li>
      </ul>

      <Route path={`${match.path}/:topicId`} component={Topic} />
      <Route
        exact
        path={match.path}
        render={() => <h3>Please select a topic.</h3>}
      />
    </div>
  );
}

function Topic({ match }) {
  return (
    <div>
      <h3>{match.params.topicId}</h3>
    </div>
  );
}

export default BasicExample;