@RequestMapping(value="/downLoadFileFormMongo.do",method=RequestMethod.GET)    @ResponseBody    public  void downLoadFileFormMongo(HttpServletRequest request,HttpServletResponse response ) throws Exception {        String filename=request.getParameter("fileId");        GridFSDBFile file = fileService.retrieveFileOne("fs", filename);        InputStream in = file.getInputStream();        filename=(String) file.get("aliases");        filename=filename.replace(" ", "");        String fileName = new String(filename.getBytes("GB2312"), "ISO_8859_1");        filename = fileName;        //response.setCharacterEncoding("UTF-8");        response.setContentType(file.getContentType());        response.setHeader("Content-Disposition", "attachment;filename=" + filename);        OutputStream out = response.getOutputStream();        byte[] buffer = new byte[2048];        int i = -1;        while ((i = in.read(buffer)) != -1) {            out.write(buffer, 0, i);        }               in.close();        out.flush();        out.close();    }