/**
* 设置cookie
* @param string $key cookie的标示
* @param mixed $val
* @param int $time 默认为一周
*/
public static function set($key, $val, $time = null)
{
if ($time === null) {
$time = time() + 604800;
}
setcookie(self::getPreKey($key), serialize($val), $time, CC::app()->baseUrl);
}
