public HttpServletResponse download(String path, HttpServletResponse response) {         try {             // path是指欲下载的文件的路径。             File file = new File(path);             // 取得文件名。             String filename = file.getName();             // 取得文件的后缀名。             String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();             // 以流的形式下载文件。             InputStream fis = new BufferedInputStream(new FileInputStream(path));             byte[] buffer = new byte[fis.available()];             fis.read(buffer);             fis.close();             // 清空response             response.reset();             // 设置response的Header             response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes()));             response.addHeader("Content-Length", "" + file.length());             OutputStream toClient = new BufferedOutputStream(response.getOutputStream());             response.setContentType("application/octet-stream");             toClient.write(buffer);             toClient.flush();             toClient.close();         } catch (IOException ex) {             ex.printStackTrace();         }         return response;     }     public void downloadLocal(HttpServletResponse response) throws FileNotFoundException {         // 下载本地文件         String fileName = "Operator.doc".toString(); // 文件的默认保存名         // 读到流中         InputStream inStream = new FileInputStream("c:/Operator.doc");// 文件的存放路径         // 设置输出的格式         response.reset();         response.setContentType("bin");         response.addHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");         // 循环取出流中的数据         byte[] b = new byte[100];         int len;         try {             while ((len = inStream.read(b)) > 0)                 response.getOutputStream().write(b, 0, len);             inStream.close();         } catch (IOException e) {             e.printStackTrace();         }     }     public void downloadNet(HttpServletResponse response) throws MalformedURLException {         // 下载网络文件         int bytesum = 0;         int byteread = 0;         URL url = new URL("windine.blogdriver.com/logo.gif");         try {             URLConnection conn = url.openConnection();             InputStream inStream = conn.getInputStream();             FileOutputStream fs = new FileOutputStream("c:/abc.gif");             byte[] buffer = new byte[1204];             int length;             while ((byteread = inStream.read(buffer)) != -1) {                 bytesum += byteread;                 System.out.println(bytesum);                 fs.write(buffer, 0, byteread);             }         } catch (FileNotFoundException e) {             e.printStackTrace();         } catch (IOException e) {             e.printStackTrace();         }     }