Springmvc实现文件下载2种实现方法

@RestController
@RequestMapping("/download")
public class DownloadController {

  @RequestMapping("/d1")
  public ResultVo<String> downloadFile(HttpServletResponse response){

    String fileName="test.png";
    try {
      //获取页面输出流
      ServletOutputStream outputStream = response.getOutputStream();
      //读取文件
      byte[] bytes = FileUtils.readFileToByteArray(new File("D:\\my-study\\test2.png"));
      //向输出流写文件
      //写之前设置响应流以附件的形式打开返回值,这样可以保证前边打开文件出错时异常可以返回给前台
      response.setHeader("Content-Disposition","attachment;filename="+fileName);
      outputStream.write(bytes);
      outputStream.flush();
      outputStream.close();
      return ResultVoUtil.success("success");
    } catch (IOException e) {
      return ResultVoUtil.error(e);
    }

  }
}

@Controller
@RequestMapping("/download2")
public class DownloadController2 {

  private final static Logger logger= LoggerFactory.getLogger(CategoryDataController.class);


  @GetMapping("/d2")
  public ResponseEntity<byte[]> download2(){
    //获取文件对象
    try {
      byte[] bytes = FileUtils.readFileToByteArray(new File("D:\\my-study\\bill-admin\\test2.png"));
      HttpHeaders headers=new HttpHeaders();
      headers.set("Content-Disposition","attachment;filename=test2.png");
      ResponseEntity<byte[]> entity=new ResponseEntity<>(bytes,headers,HttpStatus.OK);
      return entity;
    } catch (IOException e) {
      logger.error("下载出错:",e);
      return null;
    }
  }
}