2-1["dataCalculation", "one"]http://localhost:8080/-sharp/one 
dataCalculation

menu navigation

<el-menu :default-active="$router.path" class="el-menu-demo" mode="horizontal" router>
        <el-menu-item index="/" icon="el-icon-search">1</el-menu-item>
        <el-submenu index="dataCalculation">
            <template slot="title">2</template>
            <el-menu-item index="one">2-1</el-menu-item>
        </el-submenu>
    </el-menu>
    
    <router-view></router-view>

routing

 routes: [
    {
      path: "/",
      name: "HelloWorld",
      component: HelloWorld
    },
    {
      path: "/dataCalculation",
      component: DataCalculation,
      children: [
        { path: "/one", component: DataCalculationOne}
      ]
    }
  ]