1.不使用路由懒加载：

import Home from '../components/Home'
import About from '../components/About'
import User from '../components/User'

2、使用路由懒加载：

//路由懒加载的方式加载组件
const Home = () =>import('../components/Home');
const About = ()=>import('../components/About');
const User = ()=>import('../components/User');