@RequestMapping("/fileDownload.do")
public void fileDownload(RMap rmap, ModelMap model, HttpServletRequest request, HttpServletResponse response) throws IOException {
    UMap umap = commonService.selectAttachFile(rmap, model);

    String filename = (String) umap.get("original_file_name");
    String fileNm = new String(filename.getBytes("UTF-8"), "ISO-8859-1");

    response.setContentType("application/octet-stream");
    response.setHeader("Content-Disposition", "attachment;filename=" + fileNm);

    byte[] data = (byte[]) umap.get("file");
    response.getOutputStream().write(data);
}