Question

我正在尝试创建一个Rest服务，以使用Springboot从存储库下载文件。

我试图返回带有StreamingResponseBody的ResponseEntity，以将我从存储库中获取的文件作为InputStream返回。

这是我当前拥有的代码：


@GetMapping(path = "/downloadFile")
    public ResponseEntity<StreamingResponseBody> downloadFile(@RequestParam(value = "documentId") String documentId,
            HttpServletRequest request, HttpServletResponse response) throws InterruptedException, IOException {

        InputStream is = downloadService.getDocument(documentId);

        StreamingResponseBody out = outputStream -> {

            outputStream.write(IOUtils.toByteArray(is));
        };

        HttpHeaders headers = new HttpHeaders();
        headers.add("Content-Type", "text/csv");
        headers.add("Content-Disposition", "attachment; filename=" + documentId);
        headers.add("Pragma", "no-cache");
        headers.add("Cache-Control", "no-cache");

        return (new ResponseEntity<>(out, headers, HttpStatus.OK));

    }

当我使用此端点时，直接使用浏览器或邮递员，下载的文件为空。我知道OutputStream是异步写入的（在config类中启用了异步）。

如何使用此服务并完全以我使用的存储库中的文件形式编写文件？（如果可能的话，可以使用Postman进行测试）

我是否正确构建服务？

Answer 1

我修改了一点代码，在我的documentId中是要下载文件的名称。我已经测试过，它工作正常。检查下面的代码。

@GetMapping(path = "/downloadFile")
  public ResponseEntity<StreamingResponseBody> downloadFile(
      @RequestParam(value = "documentId") String documentId,
      HttpServletRequest request,
      HttpServletResponse response)
      throws InterruptedException, IOException {
    String dirPath = "E:/sure-delete/"; //Directory having the files
    InputStream inputStream = new FileInputStream(new File(dirPath + documentId));
    final StreamingResponseBody out =
        outputStream -> {
          int nRead;
          byte[] data = new byte[1024];
          while ((nRead = inputStream.read(data, 0, data.length)) != -1) {
            System.out.println("Writing some bytes of file...");
            outputStream.write(data, 0, nRead);
          }
        };
    HttpHeaders headers = new HttpHeaders();
    headers.add("Content-Type", "text/csv");
    headers.add("Content-Disposition", "attachment; filename=" + documentId);
    headers.add("Pragma", "no-cache");
    headers.add("Cache-Control", "no-cache");
    return (new ResponseEntity<>(out, headers, HttpStatus.OK));
  }

StreamingResponseBody返回空文件

1 个答案: