使用Feign实现微服务间文件下载

时间:2021-04-03 人气:0

在使用Feign做服务间调用的时候,当下载大的文件会出现堆栈溢出的情况。另外，文件管理服务（服务提供者）文件下载接口无返回值，是通过HttpServletRespoonse传输的流数据来响应，那么服务消费者该如何接受下载的数据呢？

一. 示例介绍

我们调用feign_upload_second的下载文件接口下载文件，feign_upload_second内部使用feign调用feign_upload_first实现文件下载。

二、feign_upload_first服务提供者

服务提供者下载文件接口

@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();
   }
   }
  }
  }
 }

三、feign_upload_second服务消费者

服务提供者远程调用接口

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

用feign.Response来接收

服务提供者下载文件接口

@RequestMapping(value = "/download",method = RequestMethod.GET)
 public ResponseEntity<byte[]> downFile(){
 ResponseEntity<byte[]> result=null ;
 InputStream inputStream = null;
 try {
  // feign文件下载
  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;
}

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