HttpClient Post多次调用Web API Post方法

Question

下面多次调用WebApi POST方法的Angular代码，请帮我解决这个问题。

import { Injectable } from '@angular/core';
import { HttpClient,HttpErrorResponse,HttpHeaders,HttpParams} from '@angular/common/http';
import {IUserInfo} from './user-info';
import {Observable} from 'rxjs/Observable';
import {Http,Response,RequestOptions,Headers} from '@angular/http';
import 'rxjs/add/observable/throw';
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/do';
import 'rxjs/add/operator/map';

saveNewPersonDetails(personDetails) {
    const headers = new HttpHeaders().set('Content-Type', 'application/json; charset=utf-8');

    return this._http.post(this._webApiUrl + "person",personDetails, {headers: headers})
    .subscribe(personData => this.personData=personData);
}