我在Laravel Mix中使用React Router刷新浏览器时收到错误404

我知道有几个帖子有类似的问题，但是不同的方法似乎难以理解。我想学习更多，并能够使用React.js和Laravel开发多个应用程序。

Header.js：导入文件

import React, { Component } from 'react';
import {
    BrowserRouter as Router,
    Link,
    Switch,
    Route
} from 'react-router-dom';
import Home from './Home';
import About from './About';
import Dashboard from '../admins/Dashboard';
import Contact from './Contact';

路由器（BrowserRouter）

<Router>
       <div>
            <nav className="navbar navbar-expand-lg  navbar-dark bg-dark navbar-fixed-top">
            <button className="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
                <span className="navbar-toggler-icon"></span>
            </button>

            <div className="collapse navbar-collapse" id="navbarSupportedContent">
                <ul className="navbar-nav mr-auto">
                    <li className="nav-item active">
                        <Link className="nav-link"  to="/" exact

                        >Home</Link>
                    </li>
                    <li className="nav-item">
                        <Link className="nav-link" to="/about">About Us</Link>
                    </li>

                    <li className="nav-item">
                        <Link className="nav-link" to="/contact">Contact</Link>
                    </li>
                </ul>
                <form className="form-inline my-2 my-lg-0">
                <input className="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search" />
                <button className="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
                </form>
            </div>
            </nav>
            <Switch>
                    <Route  exact path='/'  component={Home}/>
                    <Route  exact path="/about" component={About}/>
                    <Route  path='/contact' component={Contact}/>
                    <Route  path='/admins/dashboard' component={Dashboard}/>
            </Switch>
       </div>
       </Router>

当我单击链接时，它会显示链接，但是每当我尝试刷新页面时，它就会显示错误。我尝试了可能的示例，但似乎没有任何效果。我不知道我做错了什么。我一直在尝试看看如何解决。我碰到一篇文章说createBrowserHistory已被弃用，而React-router v4不支持它，即使我在努力实现该示例也是如此。有更好的解决方案吗？

我有多个页面（组件）。

Index.js

import React, { Component } from 'react';
import ReactDOM from 'react-dom';
import {
    BrowserRouter as Router,

} from 'react-router-dom';
import Header from './Header';
import Footer from './Footer';



export default class Index extends Component {

    render() {
        return (
            <div>
                <Header />

                <Footer/>
            </div>
        );
    }
}

if (document.getElementById('app')) {
    ReactDOM.render(<Index />, document.getElementById('app'));
}

about.js

import React, { Component }from 'react';
import { Redirect } from 'react-router-dom';
class About extends Component {

    constructor(props)
    {
        super(props);
    }

    render(){
        return (
            <div className="jumbotron">
                <h2>About Us</h2>
            </div>
        );
    }
}



export default About;

app.js

/**
 * First we will load all of this project's JavaScript dependencies which
 * includes React and other helpers. It's a great starting point while
 * building robust, powerful web applications using React + Laravel.
 */

require('./bootstrap');

/**
 * Next, we will create a fresh React component instance and attach it to
 * the page. Then, you may begin adding components to this application
 * or customize the JavaScript scaffolding to fit your unique needs.
 */

require('./components/Index');