angular2 http post请求

import { Http } from ‘@angular/http’;
import { Headers, RequestOptions, URLSearchParams } from ‘@angular/http’;
首先要import 这几个模块，
分别是http请求体，http请求头部，请求options，和请求发送的data，

import { Http } from '@angular/http';import { Headers, RequestOptions, URLSearchParams } from '@angular/http';import 'rxjs/add/operator/toPromise';constructor(private http: Http) {        this.headers = new Headers({ 'Content-Type': 'application/x-www-form-urlencoded;charset=UTF-8' });        this.options = new RequestOptions({ headers: this.headers });    }    private handleError(error: any): Promise<any> {        console.error('An error occurred', error); // for demo purposes only        return Promise.reject(error.message || error);    }    public getImg(): Promise<object> {        const data = new URLSearchParams();        const bodyData = {            'UUID': 'nullfy6HS'        };        data.append('body', JSON.stringify(bodyData));        data.append('tradeCode', '0002');        data.append('tradeType', 'authService');        return this.http.post(this.baseUrl, data, this.options)            .toPromise().then(response => response.json()).catch(this.handleError);    }

返回一个promise函数体