取得Blob的回应

Question

我正在尝试从服务调用中获取响应，该服务返回pdf的blob。我已经拨打了电话，但不确定如何订阅。这是我的代码

service.ts

  openDoc(val) {
    const token = this._storeService.getStoredData().access_token;
    const headers = new HttpHeaders()
      .set('Authorization', `Bearer ${token}`)
      .set('Content-Type', 'application/pdf')
      .set('observe', 'response')
      .set('responseType', 'blob');
    const options = { headers: headers };
    const url = val;
    return this._http.get<any>(url, options);
  }

component.ts

//我试图获得斑点

openDocWindow(url: string) {
    this._candidateService.openDoc(url).subscribe(res => {
      console.log("response"+ res);
      this.currentDocumentUrl = res;
      this.showDocumentWindow = true;
    });
}