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

// 定义组件
const Home = () => <h2>首页</h2>;
const About = () => <h2>关于我们</h2>;
const Contact = () => <h2>联系我们</h2>;

const App = () => (
  <Router>
    <div>
      <nav>
        <ul>
          <li>
            <Link to="/">首页</Link>
          </li>
          <li>
            <Link to="/about">关于我们</Link>
          </li>
          <li>
            <Link to="/contact">联系我们</Link>
          </li>
        </ul>
      </nav>

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

export default App;