php 后台给安卓写支付宝接口

  function getCode($order, $payment) {
        require_once './pay/aop/AopClient.php';
        $private_path = "./pay/rsa_private_key.pem"; //私钥路径
        $app_id = $payment['app_id']; //支付宝分配给开发者的应用ID
        $method = "alipay.trade.app.pay"; //接口名称
        $format = "json"; //接口格式
//        $return_url = ""; //异步通知
        $charset = "utf-8"; //编码格式
        $sign_type = "RSA2"; //接口版本
        $timestamp = date("Y-m-d H:i:s"); //时间
        $version = "1.0"; //时间
//        $notify_url = ""; //同步通知
        $biz_content = array(
            /* 业务参数 */
            'subject' => $order['order_sn'],
            'out_trade_no' => $order['order_sn'] . $order['log_id'],
            'total_amount' => $order['order_amount'],
//            'seller_id' => $payment['alipay_partner'],
        ); //请求参数
        $biz_contentarr = json_encode($biz_content, JSON_UNESCAPED_UNICODE);
        $parameter = array(
            'app_id' => $payment['app_id'], //支付宝分配给开发者的应用ID
            'method' => "alipay.trade.app.pay", //接口名称
            'format' => "json", //接口格式
//            'return_url' => "1212", //异步通知
            'charset' => "utf-8", //编码格式
            'sign_type' => "RSA2", //接口版本
            'timestamp' => date("Y-m-d H:i:s"), //时间
            'version' => "1.0", //时间
//            'notify_url' => "1212", //同步通知
            'biz_content' => $biz_contentarr,
//             'partner' => $payment['alipay_partner'],
        );
        $Client = new \AopClient();
        $paramStr = $Client->getSignContent($parameter); //组装请求签名参数     
        $sign = $Client->alonersaSign($paramStr, $private_path, 'RSA2', true); //生成签名        
        $parameter['sign'] = $sign;
        $str = $Client->getSignContentUrlencode($parameter);
        return $str;
    }