Java传统下载和SpringMVC下载

 /**
     * 传统下载
     * @param filename 文件名称
     */
    @RequestMapping(value="download", method={RequestMethod.GET, RequestMethod.POST})
    public void download(HttpServletRequest request, HttpServletResponse response, String filename) {
        String realpath = request.getServletContext().getRealPath("/");
        // 输出文件路径
        String filepath = realpath + filedir + "/" + filename;
        response.setContentType("application/octet-stream;charset=utf-8");
        response.setHeader("Content-Disposition", "attachment;filename=" + filename);
        response.addHeader("Pragma", "no-cache");
        response.addHeader("Cache-Control", "no-cache");
        try {
            OutputStream os = response.getOutputStream();
            InputStream is = new BufferedInputStream(new FileInputStream(filepath));
            byte[] buffer = new byte[4096];
            int length = 0;
            while((length = is.read(buffer)) > 0) {
                os.write(buffer, 0, length);
            }
            is.close();
            os.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * SpringMVC下载
     * @return 文件名称
     */
    @RequestMapping(value="graceDownload", method={RequestMethod.GET, RequestMethod.POST})
    public ResponseEntity<byte[]> graceDownload(HttpServletRequest request, String filename) {
        String realpath = request.getServletContext().getRealPath("/");
        // 输出文件路径
        String filepath = realpath + filedir + "/" + filename;
        byte[] byteArray = null;
        try {
            byteArray = FileUtils.readFileToByteArray(new File(filepath));
        } catch(Exception e) {
            e.printStackTrace();
        }
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
        headers.setContentDispositionFormData("attachment", filename);
        ResponseEntity<byte[]> responseEntity = new ResponseEntity<byte[]>(byteArray, headers, HttpStatus.CREATED);
        return responseEntity;
    }