挂载路由导航守卫 router

import Vue from ‘vue‘
import Router from ‘vue-router‘
import Login from ‘./components/Login.vue‘
import Home from ‘./components/Home.vue‘
import Welcome from ‘./components/Welcome.vue‘
import Users from ‘./components/user/Users.vue‘
import Rights from ‘./components/power/Rights.vue‘
import Roles from ‘./components/power/Roles.vue‘

Vue.use(Router)

const router = new Router({
  routes: [
    { path: ‘/‘, redirect: ‘/login‘ },
    { path: ‘/login‘, component: Login },
    {
      path: ‘/home‘,
      component: Home,
      redirect: ‘/welcome‘,
      children: [
        { path: ‘/welcome‘, component: Welcome },
        { path: ‘/users‘, component: Users },
        { path: ‘/rights‘, component: Rights },
        { path: ‘/roles‘, component: Roles }
      ]
    }
  ]
})

// 挂载路由导航守卫  防止 不登录  直接访问页面 
router.beforeEach((to, from, next) => {
  // to 将要访问的路径
  // from 代表从哪个路径跳转而来
  // next 是一个函数，表示放行
  //     next()  放行    next(‘/login‘)  强制跳转

  if (to.path === ‘/login‘) return next()

//项目中出了登录之外的其他API接口，必须在登录之后才能访问
// 1.2 token 只应在当前网站打开期间生效，所以将 token 保存在 sessionStorage 中

  // 获取token

const tokenStr = window.sessionStorage.getItem(‘token‘) 
if (!tokenStr) 
return next(‘/login‘) 
next()

 }) 
export default router