@RequestMapping("download")

     @ResponseBody

     public void download(HttpServletResponse response, Integer userId, String fileUrl) {

         try {

             File file=new File(fileUrl);

             String filename=file.getName();

             // 以流的形式下载文件。

             InputStream fis = new BufferedInputStream(new FileInputStream(fileUrl));

             byte[] buffer = new byte[fis.available()];

             fis.read(buffer);

             fis.close();

             // 清空response

             response.reset();

             response.setContentType("application/octet-stream;charset=UTF-8");

             String fileName = new String(filename.getBytes("gb2312"), "iso8859-1");

             response.setHeader("Content-disposition", "attachment;filename=" + fileName);

             OutputStream ouputStream = response.getOutputStream();

             ouputStream.write(buffer);

             ouputStream.flush();

             ouputStream.close();

         } catch (Exception e) {

             e.printStackTrace();

             logger.error("文件下载出现异常", e);

         }

     }