/**
     * 提交数据 
     * @param  string $url 请求Url
     * @param  string $method 请求方式
     * @param  array/string $headers Headers信息 
     * @param  array/string $params 请求参数
     * @return 返回的
     */
    // demo
    // $end_url = "";
    // $request = "<Request>";
    // $request.= "</Request>";
    // $headers = array("Content-type:application/x-www-form-urlencoded");
    // $params = array("request" => $request,"token" =>$authToken);
    // $responseXml = curlRequest($end_url, "POST", $headers, $params);
    protected function curlRequest($url, $method, $headers, $params) 
    {
        if (is_array($params)) {
            $requestString = http_build_query($params);
        } else {
            $requestString = $params ? : '';
        }
        if (empty($headers)) {
            $headers = array('Content-type: text/json'); 
        } elseif (!is_array($headers)) {
            parse_str($headers,$headers);
        }
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_VERBOSE, 1);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_POST, 1);
        switch (strtoupper($method)){  
            case "GET" : curl_setopt($ch, CURLOPT_HTTPGET, 1);break;  
            case "POST": curl_setopt($ch, CURLOPT_POST, 1);
                        curl_setopt($ch, CURLOPT_POSTFIELDS, $requestString);break;  
            case "PUT" : curl_setopt ($ch, CURLOPT_CUSTOMREQUEST, "PUT");   
                        curl_setopt($ch, CURLOPT_POSTFIELDS, $requestString);break;  
            case "DELETE":  curl_setopt ($ch, CURLOPT_CUSTOMREQUEST, "DELETE");   
                            curl_setopt($ch, CURLOPT_POSTFIELDS, $requestString);break;  
        }
        $response = curl_exec($ch);
        curl_close($ch);
        if (stristr($response, 'HTTP 404') || $response == '') {
            return array('Error' => '请求错误');
        }
        return $response;
    }