/**
*
* 申请退款，WxPayRefund中out_trade_no、transaction_id至少填一个且
* out_refund_no、total_fee、refund_fee、op_user_id为必填参数
* appid、mchid、spbill_create_ip、nonce_str不需要填入
* @param WxPayRefund $inputObj
* @param int $timeOut
* @throws WxPayException
* @return 成功时返回，其他抛异常
*/
public function refund($inputObj, $timeOut = 6)
{
$url = "https://api.mch.weixin.qq.com/secapi/pay/refund";
//检测必填参数
if (!$inputObj->isOutTradeNoSet() && !$inputObj->isTransactionIdSet()) {
throw new WxPayException("退款申请接口中，out_trade_no、transaction_id至少填一个！");
} else {
if (!$inputObj->isOutRefundNoSet()) {
throw new WxPayException("退款申请接口中，缺少必填参数out_refund_no！");
} else {
if (!$inputObj->isTotalFeeSet()) {
throw new WxPayException("退款申请接口中，缺少必填参数total_fee！");
} else {
if (!$inputObj->isRefundFeeSet()) {
throw new WxPayException("退款申请接口中，缺少必填参数refund_fee！");
} else {
if (!$inputObj->isOpUserIdSet()) {
throw new WxPayException("退款申请接口中，缺少必填参数op_user_id！");
}
}
}
}
}
$inputObj->setAppid($this->apiConfig->appid);
//公众账号ID
$inputObj->setMchId($this->apiConfig->mchid);
//商户号
$inputObj->setMchKey($this->apiConfig->mchkey);
//商户密钥
$inputObj->setNonceStr($this->getNonceStr());
//随机字符串
$inputObj->setSign();
//签名
$xml = $inputObj->toXml();
$startTimeStamp = $this->getMillisecond();
//请求开始时间
$response = $this->postXmlCurl($xml, $url, true, $timeOut);
$result = WxPayResults::init($response, $this->apiConfig->mchkey);
$this->reportCostTime($url, $startTimeStamp, $result);
//上报请求花费时间
return $result;
}