code: protected function checkDataParam()
      {
          parent::checkDataParam();
          $amount = $this->amount;
        
          // 订单号交给支付系统自己检查
  
          // 检查金额不能低于0.01
          if (bccomp($amount, Config::PAY_MIN_FEE, 2) === -1) {
              throw new PayException('支付金额不能低于 ' . Config::PAY_MIN_FEE . ' 元');
          }
  
          // 设置ip地址
          $clientIp = $this->client_ip;
          if (empty($clientIp)) {
              $this->client_ip = isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : '127.0.0.1';
          }
  
          $timeExpire = $this->timeout_express;
          if (! empty($timeExpire)) {
              $express = floor(($timeExpire - strtotime($this->dateTime)) / 60);
  
              if ($express > CmbConfig::MAX_EXPIRE_TIME || $express < 0) {// 招商规定
                  $this->timeout_express = CmbConfig::MAX_EXPIRE_TIME;
              } else {
                  $this->timeout_express = $express;
              }
          }
      }
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