php curl post请求,java后台用request文件流方式接收

php curl请求：

             $userid = 'test';
             $key   = 'testkey';
             $sign  = md5($userid.$key);
             $data='data';
             $data_string=json_encode(array('userid'=>$userid,'sign'=>$sign,'data'=>$data));
             $url = "http://xxx.WWW.com/quick/test";
             $ch = curl_init($url);
             curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
             curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);//$data JSON类型字符串
             curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
             curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json', 'Content-Length: ' . strlen($data_string)));
             $result = curl_exec($ch);
             echo "";
             print_r($result);
             echo "";
             ?>

java 后台:

 private static String getRequestStr(HttpServletRequest request) throws Exception {

       StringBuilder sb = new StringBuilder();
          BufferedReader in=new BufferedReader(new InputStreamReader(request.getInputStream(),"UTF-8"));
          String line = null;
          while ((line = in.readLine()) != null) {
              sb.append(line);
          }

      return  sb.toString();
  }