Http get 请求标头未正确返回

Question

所以我在这个函数中调用了一个 get 请求：

public exportPendingFile(): void {
    this.reset();
    this.jhiAlertService.info('bringCockpitApp.LocMgmt.messages.pendingExportStarted');

    this.mgmtService.exportPendingFile().subscribe(
      (response: HttpResponse<any>) => {
        const contentDispositionHeader = response.headers.get('Content-Disposition');
        if (contentDispositionHeader) {
          const parts: string[] = contentDispositionHeader.split(';');
          const filename = parts[1].split('=')[1];
          const blob = new Blob([response.body], { type: 'text/plain' });
          this.jhiAlertService.success('bringCockpitApp.LocMgmt.messages.pendingExportDone');
          saveAs(blob, filename);
        } else {
          this.jhiAlertService.error('bringCockpitApp.LocMgmt.messages.error');
        }
      },
      (errorResponse: LocResultMessage) => {
        this.result = this.formatResultMessage(errorResponse);
        this.jhiAlertService.error('bringCockpitApp.LocMgmt.messages.error');
      }
    );
  }

然后我检查这里是否正确发送了标头：

const contentDispositionHeader = response.headers.get('Content-Disposition');。

由于某种原因，标头没有从后端正确发送。虽然身体被正确发送...

这是TS服务功能：

exportPendingFile(): Observable<any> {
    const header = new HttpHeaders({ Accept: 'application/json' });
    const options = { headers: header };

    return this.http.get(`${this.resourceUrl}/pending/export/en`, options);
  }

这是资源：

 @GetMapping("/loc-mgmt/pending/export/{baselang}")
    @Secured({AuthoritiesConstants.ADMIN, AuthoritiesConstants.ROLE_LOCALISATION_CONTRIBUTOR})
    public ResponseEntity exportPendingTranslationFile(@Valid @PathVariable String baselang) {

            LOGGER.debug("REST request to export pending translations: {}", baselang);

        Optional<Language> potLanguage = languageService.findAll().stream().filter(lang -> lang.getCode().equals(baselang)).findAny();

        ExportFileWriter fileWriter = new ICanLocalizeXmlExportFileWriter();

        if (potLanguage.isPresent()) {

            byte[] bytes = locExportService.exportPendingTranslation(potLanguage.get(), fileWriter);

            return ResponseEntity.ok()
                .header(HttpHeaders.CONTENT_DISPOSITION, String.format("attachment;filename=pendingExport.%s", fileWriter.getFileFormat().name().toLowerCase()))
                .body(bytes);
        } else {
            return ResponseEntity.badRequest().body(new LocResultMessage("The requested base language does not exist"));
        }
    }

知道为什么正确返回标头吗？

提前致谢！