$obj = new WXRefund('參數');$obj->refundApi();

<?phpnamespace Wechat;/** * 微信退款 * @author    zzy * @version   $V1.0.0$ * @date    2018-11-9 */class WXRefund{  protected $SSLCERT_PATH ='';//證書  protected $SSLKEY_PATH = '';//證書  protected $opUserId = '';//商戶號  protected $key = '';//API密鑰  protected $appId = '';//appId  function __construct($outTradeNo, $totalFee, $outRefundNo, $refundFee)  {    //初始化退款類需要的變量    $this->totalFee = $totalFee;//訂單金額    $this->refundFee = $refundFee;//退款金額    $this->outTradeNo = $outTradeNo;//訂單號    $this->outRefundNo = $outRefundNo;//退款訂單  }  /**   * 通過微信api進行退款流程 唯一對外接口   * @return string   */  public function refundApi()  {    $parma = array(      'appid' => $this->appId,      'mch_id' => $this->opUserId,      'nonce_str' => randoms(32),//這個是隨機數 自己封裝去吧。。。      'out_refund_no' => $this->outRefundNo,      'out_trade_no' => $this->outTradeNo,      'total_fee' => intval($this->totalFee * 100),      'refund_fee' => intval($this->refundFee * 100),    );    $parma['sign'] = $this->getSign($parma, $this->key);    $xmldata = $this->arrayToXml($parma);    $xmlresult = $this->postXmlSSLCurl($xmldata, 'https://api.mch.weixin.qq.com/secapi/pay/refund');    $result = $this->arrayToXml($xmlresult);    return $result;  }  /**   * 數組轉xml   * @param $arr   * @return string   */  protected function arrayToXml($arr)  {    $xml = "<xml>";    foreach ($arr as $key => $val) {      if (is_numeric($val)) {        $xml .= "<" . $key . ">" . $val . "</" . $key . ">";      } else {        $xml .= "<" . $key . "><![CDATA[" . $val . "]]></" . $key . ">";      }    }    $xml .= "</xml>";    return $xml;  }  /**   * 簽名加密   * @param $params   * @param $key   */  protected function getSign($params, $key)  {    ksort($params, SORT_STRING);    $unSignParaString = $this->formatQueryParaMap($params, false);    return $signStr = strtoupper(md5($unSignParaString . "&key=" . $key));  }  /**   * 排序   * @param $paraMap   * @param bool $urlEncode   * @return bool|string   */  protected function formatQueryParaMap($paraMap, $urlEncode = false)  {    $buff = "";    ksort($paraMap);    foreach ($paraMap as $k => $v) {      if (null != $v && "null" != $v) {        if ($urlEncode) {          $v = urlencode($v);        }        $buff .= $k . "=" . $v . "&";      }    }    $reqPar = '';    if (strlen($buff) > 0) {      $reqPar = substr($buff, 0, strlen($buff) - 1);    }    return $reqPar;  }  /**   * 需要使用證書的請求   * @param $xml   * @param $url   * @param int $second   * @return bool|mixed   */  protected function postXmlSSLCurl($xml, $url, $second = 30)  {    $ch = curl_init();    curl_setopt($ch, CURLOPT_TIMEOUT, $second);    curl_setopt($ch, CURLOPT_URL, $url);    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);    curl_setopt($ch, CURLOPT_HEADER, FALSE);    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);    curl_setopt($ch, CURLOPT_SSLCERTTYPE, 'PEM');    curl_setopt($ch, CURLOPT_SSLCERT, $this->SSLCERT_PATH);    curl_setopt($ch, CURLOPT_SSLKEYTYPE, 'PEM');    curl_setopt($ch, CURLOPT_SSLKEY, $this->SSLKEY_PATH);    curl_setopt($ch, CURLOPT_POST, true);    curl_setopt($ch, CURLOPT_POSTFIELDS, $xml);    $data = curl_exec($ch);    if ($data) {      curl_close($ch);      return $data;    } else {      $error = curl_errno($ch);      echo "curl出錯，錯誤碼:$error" . "<br>";      curl_close($ch);      return false;    }  }}