import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

　　

    /**     * 下载飞行资料夹     *     * @param fileName     * @param response     * @return     */    @RequestMapping(value = "/download", method = {RequestMethod.POST, RequestMethod.GET})    @ResponseBody    public Object onDownload(String fileName, HttpServletResponse response) {        ResponseJson json = new ResponseJson();        HttpURLConnection con = null;        InputStream is = null;        try {            URL url = new URL(ServiceConstants.DOWNLOAD_URL_FLIGHT + fileName);    // 远程文件url，如：http://211.64.201.201/uploadfile/nyz.mp3             con = (HttpURLConnection) url.openConnection();                        response.setContentType("multipart/form-data");    // 自动识别下载文件格式            response.setHeader("Content-Disposition", "attachment;fileName=" + fileName.substring(8, fileName.length())); // 文件名            response.setHeader("Content-Length", con.getHeaderField("Content-Length")); // 文件大小            is = con.getInputStream();            byte[] b = new byte[1024];            int len = 0;            while ((len = is.read(b)) != -1) {                response.getOutputStream().write(b, 0, len);    // 仅写入读取到的字符，区别于write(b)            }            response.getOutputStream().flush();        } catch (MalformedURLException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        } finally {            try {                if (con != null) {                    con.disconnect();                }                if (is != null) {                    is.close();                }                if (response.getOutputStream() != null) {                    response.getOutputStream().close();                }            } catch (IOException e) {                e.printStackTrace();            }        }                json.setSuccess(true);        return json;    }