* 模拟post进行url请求 参数在body里面
     * @param string $url
     * @param array $post_data
     */
    function request_post($url = '', $post_data = array()) {
        if (empty($url) || empty($post_data)) {
            return false;
        }

        $o = "";
        foreach ( $post_data as $k => $v )
        {
            $o.= "$k=" . urlencode( $v ). "&" ;
        }
        $post_data = substr($o,0,-1);
        $postUrl = $url;
        $curlPost = $post_data;
        $ch = curl_init();//初始化curl
        curl_setopt($ch, CURLOPT_URL,$postUrl);//抓取指定网页
        curl_setopt($ch, CURLOPT_HEADER, 0);//设置header
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);//要求结果为字符串且输出到屏幕上
        curl_setopt($ch, CURLOPT_POST, 1);//post提交方式
        curl_setopt($ch, CURLOPT_POSTFIELDS, $curlPost);
        $data = curl_exec($ch);//运行curl
        curl_close($ch);
//        print_r($postUrl);exit;

        return $data;
    }