/**     * 下载远程服务器文件     */        @RequestMapping("/download_file")    public void downloadFile(HttpServletRequest request,HttpServletResponse response){        OutputStream os = null;        ReadableByteChannel  rbc = null;        try{
    //获取文件名                String fileExtName = "aa.jpg";                //根据条件得到文件路径                String fileurl = "http://d.hiphotos.baidu.com/zhidao/pic/item/0e2442a7d933c895623a9a8fd11373f0830200f9.jpg";                if(!fileExtName.equals("")){                    os = response.getOutputStream();                    log.info("===========文件路径==========="+fileurl);                    //获取远程文件                    URL website = new URL(ConfigInfo.getString("file_server_path")+fileurl);                    //获取数据通道                    rbc = Channels.newChannel(website.openStream());                    //获得浏览器代理信息                    final String userAgent = request.getHeader("USER-AGENT");                    //判断浏览器代理并分别设置响应给浏览器的编码格式                    String finalFileName = null;                    if(StringUtils.contains(userAgent, "MSIE")||StringUtils.contains(userAgent,"Trident")){
   //IE浏览器                        finalFileName = URLEncoder.encode(fileExtName,"UTF8");                    System.out.println("IE浏览器");                    }else if(StringUtils.contains(userAgent, "Mozilla")){
   //google,火狐浏览器                        finalFileName = new String(fileExtName.getBytes(), "ISO8859-1");                    }else{                        finalFileName = URLEncoder.encode(fileExtName,"UTF8");//其他浏览器                    }                    //设置HTTP响应头                    response.reset();//重置 响应头                    response.setContentType("application/x-download");//告知浏览器下载文件，而不是直接打开，浏览器默认为打开                    response.addHeader("Content-Disposition" ,"attachment;filename=\"" +finalFileName+ "\"");//下载文件的名称                    //读取数据                    ByteBuffer bb = ByteBuffer.allocate(1024);                    int index = -1;                    // 循环取出流中的数据                    while ((index = rbc.read(bb)) > 0){                        if (index <= 0) {                             break;                       }                       bb.position(0);                       byte[] b = new byte[index];                       bb.get(b);                       //将数据输出                       os.write(b, 0, index);                       bb.clear();//缓冲区不会被自动覆盖，需要主动调用该方法                   }                 }else{                    log.info("找不到该文件！");                }            }else{                log.info("参数异常！");            }          }catch(MalformedURLException e){            e.printStackTrace();            log.debug("获取文件错误！", e);          } catch (IOException e) {            e.printStackTrace();            log.debug("下载异常！", e);          }finally{              try {                if(rbc != null){                    rbc.close();                }                if(os != null){                    os.close();                }            } catch (IOException e) {                e.printStackTrace();                log.debug("流关闭异常！", e);            }          }    }