向后台发送请求， 数据增加成功，后台向前端返回值为显示失败， 不知道是什么原因

这是我的后台代码：

   @PostMapping("/certifications")
    @Timed
    public ResponseEntity<Certification> createCertification(@RequestBody Certification certification) throws URISyntaxException {
        log.debug("REST request to save Certification : {}", certification);
        if (certification.getId() != null) {
            throw new BadRequestAlertException("A new certification cannot already have an ID", ENTITY_NAME, "idexists");
        }
        log.info("certification的id {}", certification.getId());
        Certification result = certificationRepository.save(certification);
        log.info("save 后的certifications {}", result.getId());
        System.out.println("/api/certifications/" + result.getId());
        System.out.println(HeaderUtil.createEntityCreationAlert(ENTITY_NAME, result.getId().toString()));
        return ResponseEntity.created(new URI("/api/certifications/" + result.getId()))
            .headers(HeaderUtil.createEntityCreationAlert(ENTITY_NAME, result.getId().toString()))
            .body(result);
    }

这是我前端代码：

 this.certification.type = '身份证';
    this.certification.isverify = '未审核';
    this.certification.userId = this.user.id;
    console.log("进入examine()");
    console.log(this.certification);
    this.isSaving = true;
    if (this.certification.id !== undefined) {
      this.subscribeToSaveResponse(
        this.certificationProvider.update(this.certification));
    } else {
      this.subscribeToSaveResponse(
        this.certificationProvider.create(this.certification));
    }
    console.log("实名认证完成");


  create(certification: Certification): Observable<Certification> {
    const copy = this.convert(certification);
    return this.http.post(this.resourceUrl, copy).map((res: Response) => {
      console.log("Response 的"+res.json());
      const jsonResponse = res.json();
      console.log("jsonResponse 的"+jsonResponse);
      return this.convertItemFromServer(jsonResponse);
    });
  }

    private  subscribeToSaveResponse(result: Observable<Certification>) {
  //noinspection TypeScriptUnresolvedVariable
  console.log("subscribeToSaveResponse  里的 result"+result);
  result.subscribe((res: Certification) =>
    this.onSaveSuccess(res), (res: Response) => this.onSaveError());
}

private onSaveSuccess(result: Certification) {
  this.event.publish('carListModification', 'OK');
  this.isSaving = false;
  this.view.dismiss(result);
}

private onSaveError() {
  this.isSaving = false;
  console.log("失败");
}

调试，是否走到了方法最后一行；

使用try catch把代码包起来看看

这个问题解决了， 主要原因是引入的http 包库存在问题 ， 导致前端对返回值的解析格式错误