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

问题描述

我有一个 java/spring boot 应用程序，我想在其中构建一个 API 端点来创建并返回一个可下载的 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.但这不会将它正确地从控制器中返回，因为 ByteArrayResource::getFilename 总是返回 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;
}

我可以使用什么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

由于您使用的是 ByteArrayResource，假设 FooService 是自动装配的，您可以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);
}

这篇关于Spring Boot Controller 导出 Excel的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！