用HttpURLConnection来完成HTTP发送报文接收报文！

 public  String sendMsg(String url, byte[] PostData) {
         String content = null;
         URL urls = null;
         try {
         urls = new URL(url);
         HttpURLConnection httpURLConnection = (HttpURLConnection) urls .openConnection();
          // 设置连接时间
         httpURLConnection.setConnectTimeout(3000);
         // 打开输入流，以便从服务器获取数据
         httpURLConnection.setDoInput(true);
         // 打开输出流，以便向服务器提交数据
         httpURLConnection.setDoOutput(true);
          // 设置以POST方式提交数据
         httpURLConnection.setRequestMethod("POST");
         // 使用POST不能使用缓存
         httpURLConnection.setUseCaches(false);
         // 设置请求的类型是文本类型
         httpURLConnection.setRequestProperty("Content-Type",
         "application/x-www-form-urlencoded");
         // 设置请求体的长度
         httpURLConnection.setRequestProperty("Content-Length",
         String.valueOf(PostData.length));
         // 获得输出流，向指定的Url写入数据
         OutputStream outputStream = httpURLConnection.getOutputStream();
         outputStream.write(PostData);
         int response = httpURLConnection.getResponseCode();
                 // 获得服务器响应码
         if (response == HttpURLConnection.HTTP_OK) {
         InputStream inputStream= httpURLConnection.getInputStream();
         BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "gbk"));
                         StringBuilder builder = new StringBuilder();
                         String line = null;
                         while ((line = reader.readLine()) != null) {
                             builder.append(line).append("\n");
                         }
                         content = builder.toString();
                     }
         }catch (IOException e) {
         e.printStackTrace();
         }
         return content;
         }