React Router 4嵌套路由冲突

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

const App = () => {
  return (
    <Router>
      <Switch>
        <Route exact path="/" component={Home} />
        <Route path="/about" component={About} />
        <Route path="/users" component={Users} />
        <Route path="/users/:id" component={UserDetails} />
        <Route component={NotFound} />
      </Switch>
    </Router>
  );
};

const Home = () => <h1>Home Page</h1>;
const About = () => <h1>About Page</h1>;
const Users = () => <h1>Users Page</h1>;
const UserDetails = ({ match }) => <h1>User Details: {match.params.id}</h1>;
const NotFound = () => <h1>404 Not Found</h1>;

export default App;