Spring Boot Controller 导出 Excel

Question

我有一个 java/spring boot 应用程序，我想在其中构建一个 API 端点来创建并返回可下载的 excel 文件。这是我的控制器端点：

 @RestController
@RequestMapping("/Foo")
public class FooController {
    private final FooService fooService;

    @GetMapping("/export")
    public ResponseEntity export() {
        Resource responseFile = fooService.export();

        return ResponseEntity.ok()
                             .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename="+responseFile.getFilename())
                             .contentType(MediaType.MULTIPART_FORM_DATA)
                             .body(responseFile);
    }
}

然后是服务类

public class FooService {
  public Resource export() throws IOException {
    StringBuilder filename = new StringBuilder("Foo Export").append(" - ")
                                                            .append("Test 1.xlsx");
    return export(filename);
  }

  private ByteArrayResource export(String filename) throws IOException {
      byte[] bytes = new byte[1024];
      try (Workbook workbook = generateExcel()) {
          FileOutputStream fos = write(workbook, filename);
          fos.write(bytes);
          fos.flush();
          fos.close();
      }

      return new ByteArrayResource(bytes);
  }

  private Workbook generateExcel() {
      Workbook workbook = new XSSFWorkbook();
      Sheet sheet = workbook.createSheet();

      //create columns and rows

      return workbook;
  }

  private FileOutputStream write(final Workbook workbook, final String filename) throws IOException {
      FileOutputStream fos = new FileOutputStream(filename);
      workbook.write(fos);
      fos.close();
      return fos;
  }
}

此代码使用 Apache POI 库成功创建了正确的 excel 文件。但这不会将它正确地从控制器中返回，因为 ByteArrayResource::getFilename 总是返回 null：

 /**
 * This implementation always returns {@code null},
 * assuming that this resource type does not have a filename.
 */
@Override
public String getFilename() {
    return null;
}

我可以使用什么类型的资源来返回生成的 excel 文件？

原文由 Richard 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

由于您使用的是 ByteArrayResource ，您可以使用以下控制器代码，假设 FooService 在控制器类中自动装配。

 @RequestMapping(path = "/download_excel", method = RequestMethod.GET)
public ResponseEntity<Resource> download(String fileName) throws IOException {

ByteArrayResource resource = fooService.export(fileName);

return ResponseEntity.ok()
        .headers(headers) // add headers if any
        .contentLength(resource.contentLength())
        .contentType(MediaType.parseMediaType("application/vnd.ms-excel"))
        .body(resource);
}

原文由 Arun 发布，翻译遵循 CC BY-SA 4.0 许可协议