1、新建项目之后，在 components 文件夹下，新建 about 文件夹

2、引入二级路由，同样的是在main.js 文件下引入，这四个组件都是在 components/about 这个文件夹下，所以路径要写对

//二级路由引入
import Contact from './components/about/Contact'
import Delivery from './components/about/Delivery'
import History from './components/about/History'
import OrderingGuide from './components/about/OrderingGuide'

 

3、配置二级路由，因为二级路由都是在 about.vue 页面显示的，所以应该写在一级路由 about 的内部，在内部添加一个 children 属性，值为一个数组，数组内部存在多个路由对象，对象内部存在 path 、name、component 三个属性

//配置路由
const routes = [                       
  { path: '/', name:"indexLink", component: Home },
  { path: '/menu', name:"menuLink", component: Menu },
  { path: '/login', name:"loginLink", component: Login },
  { path: '/register', name:"registerLink", component: Register },
  { path: '/admin', name:"adminLink", component: Admin },
  { path: '/about', name:"aboutLink", component: About ,children:[
    { path: '/about/contact', name:'contactLink' , component: Contact },
    { path: './delivery', name:'deliveryLink' , component: Delivery },
    { path: './history', name:'historyLink' , component: History },
    { path: './orderingGuide', name:'orderingGuideLink' , component: OrderingGuide },
  ]},
  { path: '*', redirect:  "/menu" },
]

页面效果

 

4、配置3级路由。若是还存在三级路由，那就找到对应页面，在对应页面路由的内部继续引入，我现在是在联系我们内部引入的，所以新建一个文件夹，用来盛放三级路由

5、 重复上述引入二级路由步骤，引入三级路由，注意路由路径。components文件夹下的一级文件，就是一级路由，

about文件夹下的一级文件，就是二级路由，contact文件夹下的一级文件，就是三级路由

//三级路由引入
import Phone from './components/about/Contact/Phone'
import PersionName from './components/about/Contact/PersionName'

 6、重复上述配置二级路由步骤，配置三级路由

//配置路由
const routes = [    
   // 一级路由                   
  { path: '/', name:"indexLink", component: Home },
  { path: '/menu', name:"menuLink", component: Menu },
  { path: '/login', name:"loginLink", component: Login },
  { path: '/register', name:"registerLink", component: Register },
  { path: '/admin', name:"adminLink", component: Admin },
  { path: '/about', name:"aboutLink", redirect: "/about/contact", component: About ,children:[
   // 二级路由
    { path: '/about/contact', name:'contactLink' ,redirect:"/about/contact/phoneLink", component: Contact ,children:[
       // 三级路由
      { path: '/about/contact/phoneLink',name:"phoneLink", component: Phone },
      { path: './persionNameLink',name:"persionNameLink", component: PersionName }
    ]},
    { path: './delivery', name:'deliveryLink' , component: Delivery },
    { path: './history', name:'historyLink' , component: History },
    { path: './orderingGuide', name:'orderingGuideLink' , component: OrderingGuide },
  ]},
  { path: '*', redirect:  "/menu" },
]

7、二级路由页面。点击切换二级路由

<template>
    <div class="row mb-5">
        <div class="col-4">
            <!-- 导航 -->
            <div class="list-group mb-5">
                <router-link tag="li" :to="{name: 'historyLink'}">
                    <a class="list-group-item list-group-item-action">历史订单</a>
                </router-link>
                <router-link tag="li" :to="{name: 'contactLink'}">
                    <a class="list-group-item list-group-item-action">联系我们</a>
                </router-link>
                <router-link tag="li" :to="{name: 'orderingGuideLink'}">
                    <a class="list-group-item list-group-item-action">点餐文档</a>
                </router-link>
                <router-link tag="li" :to="{name: 'deliveryLink'}">
                    <a class="list-group-item list-group-item-action">快递信息</a>
                </router-link>
            </div>
        </div>
        <div class="col-8">
            <!-- 导航所对应的内容 点击切换对应的二级路由页面 且 展示-->
            <router-view></router-view>
        </div>
    </div>
</template>

 8、三级路由页面。点击切换三级路由

<template>
    <div class="card text-dark bg-light mb-3">
        <div class="card-header">联系我们</div>
        <div class="card-body">
            <h4 class="card-title">联系我们</h4>
            <p class="cad-text">3104527996@qq.com</p>
            <div>
                <router-link :to="{name :'phoneLink'}">电话</router-link>
                <router-link :to="{name :'persionNameLink'}">联系人</router-link>

                <!-- 点击上面的 router-link 切换对应三级路由 且 展示-->
                <router-view></router-view>
            </div>
        </div>
    </div>
</template>

 

此时，页面已经可以正常切换二级和三级路由了，但是在二级和三级路由中，没有设置默认显示页面，所以在配置 二级 和 三级 路由时设置 redirect 属性，以此来指定显示的二级 和三级 路由， ps：但是，需要注意的是，在一级路由里指定二级路由时，需要是完全一样的路径，其实

path: './delivery', 和 path: '/about/contact', 两个在页面中显示的路径都是一样的，但是指定的时候必须要写成 path: '/about/contact', 这样的

//配置路由
const routes = [                       
  { path: '/', name:"indexLink", component: Home },
  { path: '/menu', name:"menuLink", component: Menu },
  { path: '/login', name:"loginLink", component: Login },
  { path: '/register', name:"registerLink", component: Register },
  { path: '/admin', name:"adminLink", component: Admin },
  { path: '/about', name:"aboutLink", redirect: "/about/contact", component: About ,children:[
      { path: '/about/contact', name:'contactLink' ,redirect:"/about/contact/phoneLink", component: Contact ,children:[
          { path: '/about/contact/phoneLink',name:"phoneLink", component: Phone },
          { path: './persionNameLink',name:"persionNameLink", component: PersionName }
        ]
    },
    { path: './delivery', name:'deliveryLink' , component: Delivery },
    { path: './history', name:'historyLink' , component: History },
    { path: './orderingGuide', name:'orderingGuideLink' , component: OrderingGuide },
  ]},
  { path: '*', redirect:  "/menu" },
]

 还有就是，路径配置时，直接写 /about 类似的就是直接在根目录下的，若是写成 ./delivery 类似的，前面加 . 的，就代表是在当前路径下