红色字体为增改内容！！！
1、新建src/router.js
2、src/main.js
//导入vue和新建的router.js
import Vue from 'vue'
import router from './router.js'
3、src/router.js
//导入vue和vue-router
import Vue from 'vue'
import VueRouter from 'vue-router'
//使用vue-router（名称为VueRouter，可以随便取）
Vue.use(VueRouter)
//定义组件模板内容
const first = {template:'<div>这是first内容</div>'}
const second = {template:'<div>这是second内容</div>'}
const Home = {template:'<div>这是Home内容</div>'}
const firstFirst = {template:'<div>这是firstFirst内容</div>'}
const firstSecond = {template:'<div>这是firstSecond内容</div>'}
const sld={
template:`
<div class="sld">
<h2>二级组件</h2>
<router-view class="abc"></router-view>
</div>
`
}
//定义组件路径
const router = new VueRouter({
mode:"history",
base:__dirname,
routes:[ //routes
{path:"/",component:Home},
{path:"/first",component:sld,
children:[
{path:"/",component:first},
{path:"first",component:firstFirst},
{path:"second",component:firstSecond}
]
},
{path:"/second",component:second}
]
})
//使用组件
new Vue({
router,
template:`
<div id="r">
<ul>
//router-link to=“指向的组件路径”
<li><router-link to="/">/</router-link></li>
<li><router-link to="/first">first</router-link>
<ul>
<li><router-link to="/first/first">first</router-link></li>
<li><router-link to="/first/second">second</router-link></li>
</ul>
</li>
<li><router-link to="/second">second</router-link></li>
</ul>
<router-view class="abc"></router-view>
//router-view组件显示区域
</div>
`
}).$mount("#app") //组件挂载（index.html中定义的div的id为app）
4、运行npm run dev，页面显示效果为
