Angular2 HTTP GET - 将响应转换为完整对象

Question

我有这个简单的组件

import {Component} from 'angular2/core';
import {RouterLink, RouteParams} from 'angular2/router';
import {Http, Response, Headers} from 'angular2/http';
import {User} from '../../models/user';
import 'rxjs/add/operator/map';


@Component({
    template: `
        <h1>{{user.name}} {{user.surname}}</h1>
    `,
    directives: [RouterLink],
})
export class UserComponent {

    user: User;

    constructor(private routeParams: RouteParams,
        public http: Http) {
            this.user = new User();
            this.http.get('http://localhost:3000/user/' + this.routeParams.get('id'))
                .map((res: Response) => res.json())
                .subscribe((user: User) => this.user = user);
        console.log(this.user);
    }
}

为什么不subscribe将响应转换为完整User对象.当我记录user变量时,我的控制台说User {_id: undefined, name: undefined, surname: undefined, email: undefined}.但是在视图中绑定.name并且.surname正在工作..

这里发生了什么？用户实际存储在哪里？

Answer 1

在这里找到了解决方案:https://stackoverflow.com/a/29759472/2854890

我的方法现在看起来像这样:

constructor(private routeParams: RouteParams,
    public http: Http) {
    this.user = new User();
    this.http.get('http://localhost:3000/user/' + this.routeParams.get('id'))
        .map((res: Response) => res.json())
        .subscribe((json: Object) => {
            this.user = new User().fromJSON(json);
        });
}

我Serializable通过最后返回对象来增强它,所以我可以省略类似的东西

var u = new User();
u.fromJSON(...);

然后写

new User().fromJSON(json);

Serializable 类

export class Serializable {

    fromJSON(json) {
        for (var propName in json)
            this[propName] = json[propName];
        return this;
    }

}

Answer 2

好的做法是使用GET响应来使用数据

Observable<Model>

(关于Angular文档https://angular.io/guide/http)所以......

//进口

import {HttpClient} from "@angular/common/http";

//在构造函数参数列表中

private http: HttpClient

//服务方法

getUser(): Observable<User> {return this.http.get<User>({url}, {options});}

您不需要再做任何事情了.我认为这种方法最友好.