Angular 4顺序Http.post调用

import { Component } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Component({
  selector: 'app-example',
  template: `
    <button (click)="sendRequests()">发送请求</button>
  `
})
export class ExampleComponent {
  constructor(private http: HttpClient) {}

  sendRequests() {
    this.http.post('https://api.example.com/resource1', { data: 'data1' }).subscribe(response1 => {
      console.log('第一个请求成功', response1);
      
      this.http.post('https://api.example.com/resource2', { data: 'data2' }).subscribe(response2 => {
        console.log('第二个请求成功', response2);
        
        this.http.post('https://api.example.com/resource3', { data: 'data3' }).subscribe(response3 => {
          console.log('第三个请求成功', response3);
          
          // 继续调用其他请求...
        });
      });
    });
  }
}