//监听路由变化
  watch: {
   '$route':'getPath'
  },
  methods: {
   getPath(){
    this.defaultUrl = this.$route.path;
   }
  },

import Vue from 'vue';
import Router from 'vue-router';
 
Vue.use(Router);
 
import Home from './views/home';
 
import SearchProperty from './views/search/search-property';
import SearchListing from './views/search/search-listing';
import SearchContact from './views/search/search-contact';
import SearchSchool from './views/search/search-school';
 
export default new Router({
 routes: [
  {name: 'home', path: '/', component: Home},
  {name: 'search-property', path: '/search-property/:pageNum', component: SearchProperty},
  {name: 'search-contact', path: '/search-contact/:pageNum', component: SearchContact},
  {name: 'search-listing', path: '/search-listing/:pageNum', component: SearchListing},
  {name: 'search-school', path: '/search-school/:pageNum', component: SearchSchool},
 
 ],
});

<el-menu router :default-active="$route.path">
</el-menu>