老师，不知道为什么匹配不到/users/add。GET http://localhost:8080/users/js/index.js 404 (Not Found)

import React from 'react'
import ReactDOM from 'react-dom'
import { BrowserRouter as Router, Route,Switch,Redirect } from 'react-router-dom'

class PrimaryLayout extends React.Component{
    render(){
        return(
            <div className="primary-layout">
                <header>
                    Our React Router 4 App
                </header>
                <Switch>
                    <Route path="/" exact component={HomePage} />
                    <Route path="/users/add"  component={UsersAddPage} />
                    <Route path="/user"  component={UsersPage} />
                    <Redirect to="/"/>
                </Switch>
            </div>
        )
    }
}

class HomePage extends React.Component{
    render(){
        return(
            <div>Home Page</div>
        )
    }
}

class UsersAddPage extends React.Component{
    render(){
        return(
            <div>Users Add Page</div>
        )
    }
}

class UsersPage extends React.Component{
    render(){
        return(
            <div>Users Page</div>
        )
    }
}



class App extends React.Component{
    render(){
        return(
            <Router>
                <PrimaryLayout />
            </Router>
        )
    }
}




ReactDOM.render(
    <App />,
    document.getElementById('root')
);