@RequestMapping(value = "/downloadFile",method = RequestMethod.GET,consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
 public void downloadFile(HttpServletResponse response){
  String filePath = "D://1.txt";
  File file = new File(filePath);
  InputStream in = null;
  if(file.exists()){
  try {
   OutputStream out = response.getOutputStream();
   in = new FileInputStream(file);
   byte buffer[] = new byte[1024];
   int length = 0;
   while ((length = in.read(buffer)) >= 0){
   out.write(buffer,0,length);
   }
  } catch (IOException e) {
   e.printStackTrace();
  } finally {
   if(in != null){
   try {
    in.close();
   } catch (IOException e) {
    e.printStackTrace();
   }
   }
  }
  }
 }

@RequestMapping(value = "/downloadFile",method = RequestMethod.GET,consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
 Response downloadFile();

@RequestMapping(value = "/download",method = RequestMethod.GET)
 public ResponseEntity<byte[]> downFile(){
 ResponseEntity<byte[]> result=null ;
 InputStream inputStream = null;
 try {
  // feign文件下載
  Response response = uploadService.downloadFile();
  Response.Body body = response.body();
  inputStream = body.asInputStream();
  byte[] b = new byte[inputStream.available()];
  inputStream.read(b);
  HttpHeaders heads = new HttpHeaders();
  heads.add(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=123.txt");
  heads.add(HttpHeaders.CONTENT_TYPE,MediaType.APPLICATION_JSON_VALUE);

  result = new ResponseEntity <byte[]>(b,heads, HttpStatus.OK);
 } catch (IOException e) {
  e.printStackTrace();
 } finally {
  if(inputStream != null){
  try {
   inputStream.close();
  } catch (IOException e) {
   e.printStackTrace();
  }
  }
 }
 return result;
}