Angular2 Routing：它创建一个相关组件的实例是什么意思？

The router locates or creates an instance of the component associated with the route,and that component’s view is displayed in the location defined by the RouterOutlet directive.

代码示例：

import { Component } from 'angular2/core';
import {ProductListComponent} from './products/product-list.component';
import {ProductService} from './products/product.service';
import {HTTP_PROVIDERS} from 'angular2/http';
import {ROUTER_PROVIDERS,RouteConfig,ROUTER_DIRECTIVES} from 'angular2/router';
import 'rxjs/Rx'; //Load all features
import {WelcomeComponent} from './home/welcome.component'
@Component({
    selector: 'pm-app',template:`
    <div>
        <nav class='navbar navbar-default'>
            <div class='container-fluid'>
                <a class='navbar-brand'>{{pageTitle}}</a>
                <ul class='nav navbar-nav'>
                    <li><a [routerLink]="['Welcome']">Home</a></li>
                    <li><a [routerLink]="['Products']">Product List</a></li>
                </ul>
            </div>
        </nav>
        <div class='container'>
            <router-outlet></router-outlet>
        </div>
    </div>`,directives: [ROUTER_DIRECTIVES],providers: [ProductService,HTTP_PROVIDERS,ROUTER_PROVIDERS]
})
@RouteConfig([
    {path: '/welcome',name: 'Welcome',component: WelcomeComponent,useAsDefault: true },{path: '/products',name: 'Products',component: ProductListComponent}
])
export class AppComponent {
    pageTitle: string = "Acme Product Management";
}

问题是：我可以看到定位部分,但它是什么意思,它创建了一个相关组件的实例？它只是{},如果是,那么在关联的RouterOutlet指令中会显示什么？