java 下载网络资源

//下载网络资源
		@RequestMapping("downloadNet")
		@ResponseBody
		public void downloadNet(HttpServletResponse response,String  zlmc,String cclj) throws MalformedURLException {
	        // 下载网络文件
	        int bytesum = 0;
	        int byteread = 0;
	        try {
	        	URL url = new URL(cclj);//http://192.168.1.250:8091/xxx/xx.xx
		        HttpURLConnection conn = (HttpURLConnection)url.openConnection();  
		        //设置超时间为3秒
		        conn.setConnectTimeout(3*1000);
		        //防止屏蔽程序抓取而返回403错误
		        conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");

		        //得到输入流
		        InputStream inputStream = conn.getInputStream();  
		        //获取自己数组
		        byte[] buffer = readInputStream(inputStream);    
	            // 清空response
	            response.reset();
	            // 设置response的Header
	            response.addHeader("Content-Disposition", "attachment;filename="+URLEncoder.encode(zlmc, "UTF-8"));
	            response.setCharacterEncoding("UTF-8");  
	            response.addHeader("Content-Length", "" + buffer.length);
	            OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
	            response.setContentType("application/octet-stream");
	            toClient.write(buffer);
	            toClient.flush();
	            toClient.close();
	            
	        } catch (FileNotFoundException e) {
	            e.printStackTrace();
	        } catch (IOException e) {
	            e.printStackTrace();
	        }

		}

	    /**
	     * 从输入流中获取字节数组
	     * @param inputStream
	     * @return
	     * @throws IOException
	     */
	    public static  byte[] readInputStream(InputStream inputStream) throws IOException {  
	        byte[] buffer = new byte[1024];  
	        int len = 0;  
	        ByteArrayOutputStream bos = new ByteArrayOutputStream();  
	        while((len = inputStream.read(buffer)) != -1) {  
	            bos.write(buffer, 0, len);  
	        }  
	        bos.close();  
	        return bos.toByteArray();  
	    }