如何在react-router 4中单击导航链接后加载页面

npm install react-router-dom

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

class App extends React.Component {
  render() {
    return (
      <Router>
        <div>
          <nav>
            <ul>
              <li>
                <Link to="/">Home</Link>
              </li>
              <li>
                <Link to="/about">About</Link>
              </li>
              <li>
                <Link to="/contact">Contact</Link>
              </li>
            </ul>
          </nav>

          <Route path="/" exact component={Home} />
          <Route path="/about" component={About} />
          <Route path="/contact" component={Contact} />
        </div>
      </Router>
    );
  }
}

const Home = () => <h1>Home Page</h1>;
const About = () => <h1>About Page</h1>;
const Contact = () => <h1>Contact Page</h1>;

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