//src/components/LeftNav.vue
<template>
  <el-menu router :default-active="$route.path" default-active="2" class="el-menu-vertical-demo" background-color="#334157" text-color="#fff"
    active-text-color="#ffd04b" :collapse="collapsed">
    <!-- <el-menu default-active="2" :collapse="collapsed" collapse-transition router :default-active="$route.path" unique-opened class="el-menu-vertical-demo" background-color="#334157" text-color="#fff" active-text-color="#ffd04b"> -->
    <div class="logobox">
      <img class="logoimg" src="../assets/img/logo.png" alt="">
    </div>
    <el-submenu v-for="m in menus" :index="'idx_'+m.id" :key="'key_'+m.id">
      <template slot="title">
        <i :class="m.icon"></i>
        <span>{{m.text}}</span>
      </template>
      <el-menu-item v-for="m2 in m.modules" :index="m2.url" :key="'key_'+m2.id">
        <i :class="m2.icon"></i>
        <span>{{m2.text}}</span>
        <span></span>
      </el-menu-item>
    </el-submenu>
    <!-- <el-submenu index="1">
      <template slot="title">
        <i class="el-icon-location"></i>
        <span>导航一</span>
      </template>
      <el-menu-item-group>
        <template slot="title">分组一</template>
        <el-menu-item index="1-1">选项1</el-menu-item>
        <el-menu-item index="1-2">选项2</el-menu-item>
      </el-menu-item-group>
      <el-menu-item-group title="分组2">
        <el-menu-item index="1-3">选项3</el-menu-item>
      </el-menu-item-group>
      <el-submenu index="1-4">
        <template slot="title">选项4</template>
        <el-menu-item index="1-4-1">选项1</el-menu-item>
      </el-submenu>
    </el-submenu>
    <el-menu-item index="2">
      <i class="el-icon-menu"></i>
      <span slot="title">导航二</span>
    </el-menu-item>
    <el-menu-item index="3" disabled>
      <i class="el-icon-document"></i>
      <span slot="title">导航三</span>
    </el-menu-item>
    <el-menu-item index="4">
      <i class="el-icon-setting"></i>
      <span slot="title">导航四</span>
    </el-menu-item>-->
  </el-menu>
</template>
<script>
  export default {
    data() {
      return {
        collapsed: false,
        menus:[]
      }
    },
    created() {
      this.$root.Bus.$on('aaa', v => {
        this.collapsed = v;
      });
      let url = this.axios.urls.SYSTEM_MENUS;
      this.axios.get(url,{}).then(r => {
        console.log(r);
        this.menus=r.data.rows;
      }).catch(e => {
      })
    }
  }
</script>
<style>
  .el-menu-vertical-demo:not(.el-menu--collapse) {
    width: 240px;
    min-height: 400px;
  }
  .el-menu-vertical-demo:not(.el-menu--collapse) {
    border: none;
    text-align: left;
  }
  .el-menu-item-group__title {
    padding: 0px;
  }
  .el-menu-bg {
    background-color: #1f2d3d !important;
  }
  .el-menu {
    border: none;
  }
  .logobox {
    height: 40px;
    line-height: 40px;
    color: #9d9d9d;
    font-size: 20px;
    text-align: center;
    padding: 20px 0px;
  }
  .logoimg {
    height: 40px;
  }
</style>

//src/router/index.js
import Vue from 'vue'
import Router from 'vue-router'
import HelloWorld from '@/components/HelloWorld'
import AppMain from '@/components/AppMain'
import LeftNav from '@/components/LeftNav'
import TopNav from '@/components/TopNav'
import Login from '@/views/Login'
import Register from '@/views/Register'
import AddBook from '@/views/book/AddBook'
import BookList from '@/views/book/BookList'
Vue.use(Router)
export default new Router({
  routes: [{
      path: '/',
      name: 'Login',
      component: Login
    },
    {
      path: '/Register',
      name: 'Register',
      component: Register
    },
    {
      path: '/AppMain',
      name: 'AppMain',
      component: AppMain,
      children: [{
          path: '/LeftNav',
          name: 'LeftNav',
          component: LeftNav
        },
        {
          path: '/TopNav',
          name: 'TopNav',
          component: TopNav
        },
        {
          path: '/book/AddBook',
          name: 'AddBook',
          component: AddBook
        },
        {
          path: '/book/BookList',
          name: 'BookList',
          component: BookList
        }]
    }
  ]
})

//src/src/view/book/AddBook
<template>
  <h1>书籍新增</h1>
</template>
<script>
</script>
<style>
</style>

//src/src/view/book/BookList
<template>
  <h1>书籍管理</h1>
</template>
<script>
</script>
<style>
</style>

//src/componants/AppMain.vue
<template>
  <el-container class="main-container">
    <el-aside v-bind:class="asideClass">
      <LeftNav></LeftNav>
    </el-aside>
    <el-container>
      <el-header class="main-header">
        <TopNav></TopNav>
      </el-header>
      <el-main class="main-center">
        <router-view></router-view>
      </el-main>
    </el-container>
  </el-container>
</template>
<script>
  // 导入组件
  import TopNav from '@/components/TopNav.vue'
  import LeftNav from '@/components/LeftNav.vue'
  // 导出模块
  export default {
    components: {
      TopNav,
      LeftNav
    },
    data() {
      return {
        asideClass: 'main-aside'
      }
    },
    created() {
      this.$root.Bus.$on('aaa', v => {
        this.asideClass = v ? 'main-aside-collapsed' : 'main-aside';
      })
    }
  };
</script>
<style scoped>
  .main-container {
    height: 100%;
    width: 100%;
    box-sizing: border-box;
  }
  .main-aside-collapsed {
    /* 在CSS中，通过对某一样式声明! important ，可以更改默认的CSS样式优先级规则，使该条样式属性声明具有最高优先级 */
    width: 64px !important;
    height: 100%;
    background-color: #334157;
    margin: 0px;
  }
  .main-aside {
    width: 240px !important;
    height: 100%;
    background-color: #334157;
    margin: 0px;
  }
  .main-header,
  .main-center {
    padding: 0px;
    border-left: 2px solid #333;
  }
</style>