我react router在我的项目中使用，当我点击登录按钮时，它renders是App组件的内容，但将它们显示在same page. 我想new page在我点击时显示login，帮帮我

import React, { Component } from 'react';
import * as service from '../services/service';
import '../App.css'
import '../index.css'
import App from'../App'
import { Link, Redirect, Router, Route, browserHistory,IndexRoute } from 'react-router';
// import createHistory from 'history/createBrowserHistory'

class Login extends Component {
  constructor(props) {
    super(props);
    this.state = {
      messages: []
    }
  }
  onSubmit() {
    browserHistory.push('/world');
    }
  render() {
    const { messages } = this.state;
    return (
      <div className="App">
        <header>
          <h2> Doctor Login Page </h2>
        </header>
        <form>

        <Router history={browserHistory}>
        <Route path="/world" component={App}/>
      </Router>
          <br /><br /><br />
          Username: <input name='email' placeholder='Email' /><br /><br />
          Password: <input name='password' placeholder='Password' type='password' />
          <br /><br />
          <button onClick={() => this.onSubmit()}>Login</button>
        </form>
      </div>
    );
  }
}

export default Login;