Spring Boot Controller导出Excel [英] Spring Boot Controller export an Excel

问题描述

我有一个Java/Spring引导应用程序，我想在其中构建一个API端点，该端点创建并返回可下载的excel文件.这是我的控制器端点:

I have a java/spring boot application where I want to build an API endpoint that creates and returns a downloadable excel file. Here is my controller endpoint:

@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.但这不会将其正确地从控制器中退回，因为 ByteArrayResource :: getFilename 始终返回null:

This code successfully creates the proper excel file using the Apache POI library. But this won't return it out of the controller properly because ByteArrayResource::getFilename always returns null:

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

我可以使用哪种类型的资源来返回生成的excel文件?

What type of resource can I use to return the generated excel file?

推荐答案

由于使用的是 ByteArrayResource ，因此可以在假定 FooService 已自动接线的情况下使用以下控制器代码在控制器类中.

Since you are using ByteArrayResource, you can use the below controller code assuming that the FooService is autowired in the controller class.

@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);
}

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