Angular 2路由如何创建服务中的路由器对象？

import { Injectable } from '@angular/core';
import { Router } from '@angular/router';

@Injectable()
export class MyService {
  constructor(private router: Router) { }
}

@Injectable()
export class MyService {
  private routerObj: Router;

  constructor(private router: Router) {
    this.routerObj = router;
  }
}