url angular 2中的Http Post param

import { HttpModule, Http } from '@angular/http';

constructor(private http: Http) { }

const url = 'http://example.com/api/endpoint';
const params = { key1: 'value1', key2: 'value2' };

this.http.post(url, params)
  .subscribe(response => {
    console.log(response.json());
  }, error => {
    console.error(error);
  });

import { Headers } from '@angular/http';

const headers = new Headers({ 'Content-Type': 'application/x-www-form-urlencoded' });

this.http.post(url, params, { headers: headers })
  .subscribe(response => {
    console.log(response.json());
  }, error => {
    console.error(error);
  });