beforeEach函数 这是路由跳转前处理的函数

import PageNotFound from '@/views/pages/404.vue'
Vue.use(Router)
const routes=[
  {
    path: '*',
    name: 'PageNotFound',
    component: PageNotFound,
  },
]


const router = new Router({
  mode: 'history',
  routes: routes
})

router.beforeEach((to, from, next) => {
  //  从其他地方访问是否有这个地址
    if(to.matched.length == 0){
      from.path ? next({name: from.name}) : next('*')
    }
    next();
});

第二种方法就是重定向地址 同上

修改routes中的地址

  {
    path: '/404',
    name: 'PageNotFound',
    component: PageNotFound,
  },
  {
    path:'*',
    redirect:'/404'
   }