angular8如何封装http服务

// 引入封装好的http服务

constructor(private http: HttpService) { }

/**

   * 测试get方法

   * @param successCallback 成功的回调

   * @param failCallback 失败的回调

   */

public testGet(url: string, successCallback?: Function, failCallback?: Function) {

  const httpOptions = {

    headers: new HttpHeaders({

      'Content-Type': 'application/json; charset=UTF-8'

    })

  };

  this.http.get(url, httpOptions.headers).subscribe(

    (res: any) => {

      successCallback(res); // 成功走sucessCallback

    }, (err: HttpErrorResponse) => {

      failCallback(err);         // 失败

    }

  );

}