public function __construct()
{
$className = Utils::getShortName($this);
$this->isAvailable();
$config = Option::get('MAIL_' . $className);
if (!$config) {
throw new Error("邮件模块 " . $className . " 配置不完整,无法使用。");
}
$this->config = json_decode($config, true);
}