/**  * 微信 退款 操作  */  public function refund($out_trade_no, $total_fee)
    {
        $parma = array( 'appid' => $this->appid, 'mch_id' => $this->mch_id, 'sub_mch_id' => $this->sub_mch_id, 'nonce_str' => $this->createNoncestr(), 'out_refund_no' => date("YmdHis"), 'out_trade_no' => $out_trade_no, 'total_fee' => $total_fee * 100, 'refund_fee' => $total_fee * 100,
        );
        $parma['sign'] = $this->getSign($parma);
        $xmldata = $this->arrayToXml($parma);
        $xmlresult = $this->postXmlSSLCurl($xmldata, 'https://api.mch.weixin.qq.com/secapi/pay/refund');
        $result = $this->xmlToArray($xmlresult); if ($result['result_code'] == 'SUCCESS') { return true;
        } else { return false;
        }
    } //作用：产生随机字符串，不长于32位  private function createNoncestr($length = 32)
    {
        $chars = "abcdefghijklmnopqrstuvwxyz0123456789";
        $str = ""; for ($i = 0; $i < $length; $i++) {
            $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
        } return $str;
    } //作用：生成签名  private function getSign($Obj)
    { foreach ($Obj as $k => $v) {
            $Parameters[$k] = $v;
        } //签名步骤一：按字典序排序参数  ksort($Parameters);
        $String = $this->formatBizQueryParaMap($Parameters, false); //签名步骤二：在string后加入KEY  $String = $String . "&key=" . $this->key; //签名步骤三：MD5加密  $String = md5($String); //签名步骤四：所有字符转为大写  $result_ = strtoupper($String); return $result_;
    } ///作用：格式化参数，签名过程需要使用  private function formatBizQueryParaMap($paraMap, $urlencode)
    {
        $buff = ""; ksort($paraMap); foreach ($paraMap as $k => $v) { if ($urlencode) {
                $v = urlencode($v);
            }
            $buff .= $k . "=" . $v . "&";
        }
        $reqPar = ''; if (strlen($buff) > 0) {
            $reqPar = substr($buff, 0, strlen($buff) - 1);
        } return $reqPar;
    } //数组转换成xml  private function arrayToXml($arr)
    {
        $xml = "<root>"; foreach ($arr as $key => $val) { if (is_array($val)) {
                $xml .= "<" . $key . ">" . $this->arrayToXml($val) . "</" . $key . ">";
            } else {
                $xml .= "<" . $key . ">" . $val . "</" . $key . ">";
            }
        }
        $xml .= "</root>"; return $xml;
    } //需要使用证书的请求  private function postXmlSSLCurl($xml, $url, $second = 30)
    {
        $ch = curl_init(); //超时时间  curl_setopt($ch, CURLOPT_TIMEOUT, $second); //这里设置代理，如果有的话  //curl_setopt($ch,CURLOPT_PROXY, '8.8.8.8');  //curl_setopt($ch,CURLOPT_PROXYPORT, 8080);  curl_setopt($ch, CURLOPT_URL, $url); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE); //设置header  curl_setopt($ch, CURLOPT_HEADER, FALSE); //要求结果为字符串且输出到屏幕上  curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE); //设置证书  //使用证书：cert 与 key 分别属于两个.pem文件  //默认格式为PEM，可以注释  curl_setopt($ch, CURLOPT_SSLCERTTYPE, 'PEM'); curl_setopt($ch, CURLOPT_SSLCERT, base_path() . '/public/cret/apiclient_cert.pem'); //默认格式为PEM，可以注释  curl_setopt($ch, CURLOPT_SSLKEYTYPE, 'PEM'); curl_setopt($ch, CURLOPT_SSLKEY, base_path() . '/public/cret/apiclient_key.pem'); //post提交方式  curl_setopt($ch, CURLOPT_POST, true); curl_setopt($ch, CURLOPT_POSTFIELDS, $xml);
        $data = curl_exec($ch); //返回结果  if ($data) { curl_close($ch); return $data;
        } else {
            $error = curl_errno($ch); echo "curl出错，错误码:$error" . "<br>"; curl_close($ch); return false;
        }
    } //xml转换成数组  private function xmlToArray($xml)
    { //禁止引用外部xml实体  libxml_disable_entity_loader(true);
        $xmlstring = simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA);
        $val = json_decode(json_encode($xmlstring), true); return $val;
    }