Angular 7决定文件扩展名

Question

我具有以下触发数据导出并下载响应的Angular组件：

  exportData(): void {
    this.exporting = true;
    this.changeButton();
    const options = {headers: new HttpHeaders({'Content-Type': 'application/json'}), responseType: 'arraybuffer' as 'json'};
    this.http.post('http://localhost:8080/export/lb', JSON.stringify(this.filter), options)
      .subscribe((next) => {
        // @ts-ignore
        const file = new Blob([next], {type: 'application/pdf'});
        const fileURL = URL.createObjectURL(file);
        window.open(fileURL);
        this.exporting = false;
        this.changeButton();
      }, error1 => {
        this.exporting = false;
        this.changeButton();
      });
  }

过滤器现在将包含一个新的导出格式选项CSV。
这是我的后端代码：

@CrossOrigin
@RequestMapping(value = "/export/lb", method = RequestMethod.POST)
public ResponseEntity<byte[]> getFilterLBPDF(@RequestBody PdfExportFilter filter) throws IOException, DocumentException {
    F5StructureExporter writer = ExporterFactory.getInstance.getExporter(filter);
    Path filePath = Paths.get(writer.getBaseTempDir() + "/filteredLBexport.pdf");
    writer.exportData();
    F5StructureExporter writerCsv = new FilteredCsvLbExporter(filter);
    writerCsv.exportData();
    return new ResponseEntity<byte[]>(readPdfBytes(filePath), getHttpHeaders("filtered_export"), HttpStatus.OK);
}

private HttpHeaders getHttpHeaders(String file) {
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.parseMediaType("application/pdf"));
    String filename = new Date() + "_" + file;
    headers.setContentDispositionFormData(filename, filename);
    headers.setCacheControl("must-revalidate, post-check=0, pre-check=0");
    return headers;
}

private byte[] readPdfBytes(Path path) {
    try {
        return Files.readAllBytes(path);
    } catch (IOException e) {
        e.printStackTrace();
    }
    return new byte[0];
}

现在，我希望也能返回CSV，是否有机会在Angular中确定PDF或CSV？

非常感谢。