在angular、rxjs中依次发出两个http请求

import { HttpClientModule } from '@angular/common/http';

@NgModule({
  imports: [
    HttpClientModule
  ],
  ...
})
export class AppModule { }

import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';

constructor(private http: HttpClient) { }

public getFirstData(): Observable<any> {
  return this.http.get('https://api.example.com/first');
}

public getSecondData(): Observable<any> {
  return this.http.get('https://api.example.com/second');
}

public fetchData(): void {
  this.getFirstData().subscribe(
    firstResponse => {
      // 处理第一个请求的响应数据
      console.log(firstResponse);
      
      // 发出第二个请求
      this.getSecondData().subscribe(
        secondResponse => {
          // 处理第二个请求的响应数据
          console.log(secondResponse);
        },
        error => {
          // 处理第二个请求的错误
          console.error(error);
        }
      );
    },
    error => {
      // 处理第一个请求的错误
      console.error(error);
    }
  );
}