java类访问一个网络URL,获取压缩格式的下载文件

/**
 *url:访问的网络地址
 *paramData：需要提交的参数
 *sFilePath  :访问网络地址后下载到本地的路径 c:/test.txt
 * */
 public void downLoadFiletoLocal(String sFilePath, String paramData, URL url) {

  try {
   URLConnection conn = url.openConnection();
   conn.setDoOutput(true);
   //发送域信息
   OutputStreamWriter outwr = new OutputStreamWriter(conn.getOutputStream());
   outwr.write(paramData);//这里组织域信息
   outwr.flush();
   outwr.close();
   //获取返回数据
   InputStream in = conn.getInputStream();
   int n = 0;
   byte[] buf = new byte[4 * 1024];
   FileOutputStream out = new FileOutputStream(new File(sFilePath));
   while ((n = in.read(buf, 0, buf.length)) != -1) {
    out.write(buf, 0, n);
   }
   out.close();
   in.close();

  } catch (IOException e) {
   e.printStackTrace();
  }
 }