flag = $flag; $this->message = $message ?? ($flag ? '操作成功' : '操作失败'); $this->data = $data; } public static function success(?string $message = '操作成功', mixed $data = null): self { return new self(true, $message, $data); } public static function fail(?string $message = '操作失败', mixed $data = null): self { return new self(false, $message, $data); } }