在router.js中，

由于路由是从上到下执行的，只要在路由配置中最后面放个*号就可以了，例如：

最后一个就是404

import Vue from 'vue'
import Router from 'vue-router'
import HelloWorld from '@/components/index'
import na from '@/components/newDetail'
import ga from '@/components/goodlist'
import notfount from '@/components/404'
Vue.use(Router)

export default new Router({
  routes: [
    {
      path: '/',
      name: 'HelloWorld',
      component: HelloWorld
    },
    {
      path: '/newDetail',
      name: 'newDetail',
      component: na
    },
    {
      path: '/goodlist',
      name: 'goodlist',
      component: ga
    },
    {
  path: '*',
    name: 'notfount',
    component: notfount
}
  ]
})