setOutTradeNo($out_trade_no); $RequestBuilder->setTradeNo($trade_no); $RequestBuilder->setRefundAmount($refund_amount); $RequestBuilder->setOutRequestNo($out_request_no); $RequestBuilder->setRefundReason($refund_reason); $aop = new AlipayTradeService($config); /** * alipay.trade.refund (统一收单交易退款接口) * @param $builder 业务参数，使用buildmodel中的对象生成。 * @return $response 支付宝返回的信息 */ $response = $aop->Refund($RequestBuilder); var_dump($response);; ?>