详解AngularJS2 Http服务

import 'rxjs/add/operator/toPromise';

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

import { Headers, Http } from '@angular/http';

import 'rxjs/add/operator/toPromise';

import { Hero } from './hero';
 private heroesUrl = 'api/heroes'; // URL to web api

 constructor(private http: Http) { }

 getHeroes(): Promise<Hero[]> {
  return this.http.get(this.heroesUrl)
        .toPromise()
        .then(response => response.json().data as Hero[])
        .catch(this.handleError);
 }

 private handleError(error: any): Promise<any> {
  console.error('An error occurred', error); // for demo purposes only
  return Promise.reject(error.message || error);
 }

.then(response => response.json().data as Hero[])

  getHero(id: number): Promise<Hero> {
    const url = `${this.heroesUrl}/${id}`;
    return this.http.get(url).toPromise()
   .then(response => response.json().data as Hero)
   .catch(this.handleError);
  }

  private headers = new Headers({'Content-Type': 'application/json'});
  update(hero: Hero): Promise<Hero> {
  const url = `${this.heroesUrl}/${hero.id}`;
  return this.http
  .put(url, JSON.stringify(hero), {headers: this.headers})
  .toPromise()
  .then(() => hero)
  .catch(this.handleError);
}

   save(): void {
   this.heroService.update(this.hero)
    .then(() => this.goBack());
  }

 create(name: string): Promise<Hero> {
 return this.http
  .post(this.heroesUrl, JSON.stringify({name: name}), {headers: this.headers})
  .toPromise()
  .then(res => res.json().data)
  .catch(this.handleError);
}

  delete(id: number): Promise<void> {
   const url = `${this.heroesUrl}/${id}`;
   return this.http.delete(url, {headers: this.headers})
    .toPromise()
    .then(() => null)
    .catch(this.handleError);
  }

delete(hero: Hero): void {
 this.heroService
   .delete(hero.id)
   .then(() => {
    this.heroes = this.heroes.filter(h => h !== hero);
    if (this.selectedHero === hero) { this.selectedHero = null; }
   });
}