after using browserHistory, the dva can jump to the second-level route normally after configuring the second-level route, but it cannot be refreshed. Refreshing will cause the page to become blank. I have found a solution on the Internet, which is mainly based on the server configuration. I want to be able to refresh the blank during development. I do not know how to configure 
 index.js to use 
 import createHistory from "history/createBrowserHistory"; 
 const app = dva ({history: createHistory ()}). 
 Main.js 
 class Main extends React.Component {
render() {
    return (
        <div>
            <div>
                <Link to="/first" >1</Link><Link to="/second" >2</Link>
            </div>
            <div>
                <Route path="/" render={() => (
                    <div>
                        <Switch>
                            <Route path="/first" exact component={First} />
                            <Route path="/second" component={Second} />
                            <Route path="/first/three" component={Three} />
                        </Switch>
                    </div>
                )} />
            </div>
        </div>
    );
}}
 First.js 
 class First extends React.Component {
render() {
    return (
        <div>
            <Link to="/first/three"></Link>
        </div>
    );
}}
 Second.js and Three.js 
 class Second extends React.Component {
render() {
    return(
        <div></div>
    );
}}
 


/first/three
 
 
page will disappear, ask for guidance
