if (!is_null($value)) {
$format = !empty($param) ? $param : $this->dateFormat;
$value = $this->formatDateTime($value, $format);
}改为 if (!is_null($value)) {
$format = !empty($param) ? $param : $this->dateFormat;
$value = !empty($value) ? $this->formatDateTime($value, $format) : '';
} 