java下载文件的种方式

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();
         }
     } 

//支持在线打开文件的一种方式 

    public void downLoad(String filePath, HttpServletResponse response, boolean isOnLine) throws Exception { 

        File f = new File(filePath); 

        if (!f.exists()) { 

            response.sendError(404, "File not found!"); 

            return; 

        } 

        BufferedInputStream br = new BufferedInputStream(new FileInputStream(f)); 

        byte[] buf = new byte[1024]; 

        int len = 0; 

        response.reset(); // 非常重要 

        if (isOnLine) { // 在线打开方式 

            URL u = new URL("file:///" + filePath); 

            response.setContentType(u.openConnection().getContentType()); 

            response.setHeader("Content-Disposition", "inline; filename=" + f.getName()); 

            // 文件名应该编码成UTF-8 

        } else { // 纯下载方式 

            response.setContentType("application/x-msdownload"); 

            response.setHeader("Content-Disposition", "attachment; filename=" + f.getName()); 

        } 

        OutputStream out = response.getOutputStream(); 

        while ((len = br.read(buf)) > 0) 

            out.write(buf, 0, len); 

        br.close(); 

        out.close();