angular2 Http请求

提供HTTP服务

HttpModule并不是Angular的核心模块。 它是Angular用来进行Web访问的一种可选方式，并位于一个名叫@angular/http的独立附属模块中.

编辑app.module.ts

import { HttpModule, JsonpModule } from '@angular/http';@NgModule({  imports: [    HttpModule,    JsonpModule  ],})

angular-in-memory-web-api

npm install angular-in-memory-web-api --save-dev

This in-memory web api service processes an HTTP request and returns an Observable of HTTP Response object in the manner of a RESTy web api.

:base/:collectionName/:id?GET api/heroes          // all heroesGET api/heroes/42       // the character with id=42GET api/heroes?name=^j  // 'j' is a regex; returns heroes whose name starting with 'j' or 'J'GET api/heroes.json/42  // ignores the ".json"

之前测试时用的app/mock/user_data_memory_mock.ts数据

import {User} from '../model/User';import { InMemoryDbService } from 'angular-in-memory-web-api';export class UserDataMemoryMock implements InMemoryDbService{  createDb() {    const users: User[] = [        new User('chenjianhua_a', 21, '[e-mail]', '123456'),        new User('chenjianhua_b', 22, '[e-mail]', '123456'),        new User('chenjianhua_c', 23, '[e-mail]', '123456'),        new User('chenjianhua_d', 24, '[e-mail]', '123456'),        new User('chenjianhua_e', 25, '[e-mail]', '123456'),        new User('chenjianhua_f', 26, '[e-mail]', '123456'),        ];    return {users};  }}

编辑app.module.ts

import { InMemoryWebApiModule } from 'angular-in-memory-web-api';import { UserDataMemoryMock } from './mock/user_data_memory_mock';@NgModule({  imports: [    InMemoryWebApiModule.forRoot(UserDataMemoryMock),  ]})

导入InMemoryWebApiModule并将其加入到模块的imports数组。 InMemoryWebApiModule将Http客户端模拟的后端服务
forRoot()配置方法需要UserMemoryMockService类实例，用来向内存数据库填充数据

编辑app/service/user.restful.service.ts

import {Injectable} from '@angular/core';import { Headers, Http } from '@angular/http';import 'rxjs/add/operator/toPromise';import { User } from '../model/User';import { Logger } from './logger.service';@Injectable()export class UserService {    private USERURL = 'api/users';    private headers = new Headers({'Content-Type': 'application/json'});    constructor(private Log: Logger,    private http: Http) { }    getUserByName(name: string): Promise<User> {    const url = `${this.USERURL}/?name=${name}`;    return this.http.get(url)        .toPromise()        .then(response => response.json().data as User)        .catch(this.handleError);    }    getUsers(): Promise<User[]> {        console.log('Get User!');        return this.http.get(this.USERURL)        .toPromise()        .then(response => response.json().data as User[])        .catch(this.handleError);    }    create(name: string): Promise<User> {    return this.http        .post(this.USERURL, JSON.stringify({name: name}), {headers: this.headers})        .toPromise()        .then(res => res.json().data as User)        .catch(this.handleError);    }    private handleError(error: any): Promise<any>{        console.log('An error occurred :', error);        return Promise.reject(error.message);    }}

编辑app/components/app-loginform/app.loginform.ts

import { Component, OnInit } from '@angular/core';import { Logger } from '../../service/logger.service';import { UserService } from '../../service/user.restful.service';import { User } from '../../model/User';import { Subject } from 'rxjs/Subject';@Component({  selector: 'app-loginform',  templateUrl: './app.loginform.html',  styleUrls: ['./app.loginform.css'],  providers: [    Logger,    UserService  ]})export class AppLoginFormComponent implements OnInit {    users: User[];    submitted = false;    model = new User('1', 'fangfang', 22, '[e-mail]', '123456');    constructor(        private Log: Logger,        private userService: UserService    ){}    ngOnInit(): void{        this.userService        .getUsers()        .then( users => this.users = users);    }    onSubmit(): void {        this.userService.getUserByName(this.model.name)        .then( user => {            console.log('user.name', user[0].name);            console.log('user.password', user[0].password);            if(user[0].name === this.model.name            && user[0].password === this.model.password){                this.Log.log('login success!');                this.submitted = true;            }else{                this.Log.log('login failed!');                this.submitted = false;            }        })        .catch(errorMsg => console.log(errorMsg));    }}

HTTP Promise

Angular 的http.get返回一个 RxJS 的Observable对象。 Observable是一个管理异步数据流的强力方式。
现在，我们先利用toPromise方法把Observable直接转换成Promise对象

参考

• RxJs 介绍
• angular-in-memory-web-api