render() {
return (
<div>
        <Header />
        <Switch>
          <Route exact path='/' render={() => {
            return <MusicPlayer selectedMusic={this.state.selectedMusic} />
          }} />

          <Route path='/list' render={() => {
            return (
              <MusicList
                musics={this.state.musics}
                curMusic={this.state.selectedMusic}
                onSelectedMusic={(selectedMusic) => { this.setState({ selectedMusic }) }} />
            )
          }} />
        </Switch>
      </div >
)
}

import 部分：

import { Switch, Route, Router } from 'react-router'

import createBrowserHistory from 'history/createBrowserHistory'

let history = createBrowserHistory()

root组件return 部分（没有将root拆分出来为app组件，合在一起的）：

   return (

<Router history={history}>

<div>

<Header />

<Switch>

<Route exact path='/' render={() => (

<Player currentMusitItem={this.state.currentMusitItem}></Player>

)}></Route>

<Route exact path='/list' render={() => (

<MusicList musicList={this.state.musicList}></MusicList>

)}></Route>

</Switch>

</div>

</Router>

)

没有hashHistory   引用

import {  HashRouter as Router, Link,Switch} from 'react-router-dom';

<Router>

          <Switch>

            <Route exact path="/" render={(props) => (<Player {...props} currentMusicItem={this.state.currentMusicItem}></Player>)}/>

            <Route  path="/list" render={(props) => (<PlayerList {...props} currentMusicItem={this.state.currentMusicItem} musiclist={this.state.musiclist}></PlayerList>)} />

          </Switch>

  </Router>