最新版本的react-router 4.x，官方文档只有英文的，无奈英文看起来比较费力，大部分人是不是跟我一样，先找中文资料，实在没办法再去看英文原版，嘿嘿嘿。
找不到中文的，那我就自己来翻译一下吧，边翻译边学习。

指南

• 快速开始

1、创建一个react项目

npm install -g create-react-app
create-react-app demo-app
cd demo-app

2、引入react-router-dom

npm install react-router-dom

3、简单路由举例

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

function Index() {
  return <h2>Home</h2>;
}

function About() {
  return <h2>About</h2>;
}

function Users() {
  return <h2>Users</h2>;
}

function AppRouter() {
  return (
    <Router>
      <div>
        <nav>
          <ul>
            <li><Link to="/">Home</Link></li>
            <li><Link to="/about/">About</Link></li>
            <li><Link to="/users/">Users</Link></li>
          </ul>
        </nav>

        <Route path="/" exact component={Index} />
        <Route path="/about/" component={About} />
        <Route path="/users/" component={Users} />
      </div>
    </Router>
  );
}

export default AppRouter;

4、嵌套路由举例

/topics路径加载Topics组件，而Topics组件又根据动态参数id进一步渲染不同的内容
import React from "react";
import { BrowserRouter as Router, Route, Link } from "react-router-dom";

function App() {
  return (
    <Router>
      <div>
        {* 导航头Header组件 *}
        <Header />

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

function Home() {
  return <h2>Home</h2>;
}

function About() {
  return <h2>About</h2>;
}

function Topics({ match }) {
  return (
    <div>
      <h2>Topics</h2>

      <ul>
        <li><Link to={`${match.url}/components`}>Components</Link></li>
        <li><Link to={`${match.url}/props-v-state`}>Props v. State</Link></li>
      </ul>
      {*在这里根据参数id渲染Topic组件的内容
        （这个参数id就是上面<Link>标签中to属性/后面的值，分别是component, props-v-state）
       *}
      <Route path={`${match.path}/:id`} component={Topic} />

      {*这里是默认显示的内容*}
      <Route exact path={match.path} render={() => <h3>Please select a topic.</h3>}/>
    </div>
  );
}

function Topic({ match }) {
  return <h3>Requested Param: {match.params.id}</h3>;
}

export default App;