這篇文章主要介紹了angular2中Http請求原理與用法,結合實例形式分析了AngularJS中http相關模組實現http服務請求與相應的相關操作技巧,需要的朋友可以參考下
#本文實例講述了angular2中Http請求原理與用法。分享給大家供大家參考，具體如下：
提供HTTP服務
HttpModule並不是Angular的核心模組。它是Angular用來進行Web存取的一種可選方式，並位於一個名叫@angular/http的獨立附屬模組中.
編輯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 heroes GET api/heroes/42 // the character with id=42 GET 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"
之前測試時用的app/mock/user_data_memory_mock.ts資料
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, '2290910211@qq.com', '123456'),
new User('chenjianhua_b', 22, '2290910211@qq.com', '123456'),
new User('chenjianhua_c', 23, '2290910211@qq.com', '123456'),
new User('chenjianhua_d', 24, '2290910211@qq.com', '123456'),
new User('chenjianhua_e', 25, '2290910211@qq.com', '123456'),
new User('chenjianhua_f', 26, '2290910211@qq.com', '123456'),
];
return {users};
}
}編輯app.module.ts
#import { InMemoryWebApiModule } from 'angular-in-memory-web-api';
import { UserDataMemoryMock } from './mock/user_data_memory_mock';
@NgModule({
imports: [
InMemoryWebApiModule.forRoot(UserDataMemoryMock),
]
})匯入InMemoryWebApiModule並將其加入到模組的imports陣列。 InMemoryWebApiModule將Http客戶端模擬的後端服務forRoot()設定方法需要UserMemoryMockService類別實例，用來填入記憶體資料庫
編輯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);
}
}#編輯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, '2290910211@qq.com', '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傳回一個RxJS 的Observable物件。 Observable是一個管理非同步資料流的強力方式。
現在，我們先利用toPromise方法把Observable直接轉換成Promise物件
上面是我整理給大家的，希望今後會對大家有幫助。
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