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

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

    String fileName="test.png";
    try {
      //獲取頁面輸出流
      ServletOutputStream outputStream = response.getOutputStream();
      //讀取文件
      byte[] bytes = FileUtils.readFileToByteArray(new File("D:\\my-study\\test2.png"));
      //向輸出流寫文件
      //寫之前設(shè)置響應(yīng)流以附件的形式打開返回值,這樣可以保證前邊打開文件出錯時異常可以返回給前臺
      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(){
    //獲取文件對象
    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("下載出錯:",e);
      return null;
    }
  }
}