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 {
        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