/**
* 返回COOKIE中得UUID，如果没有则生成一个并写入COOKIE中
* @author zeroq
* @return type
*/
protected function getUuid()
{
if (isset($_COOKIE['uuid'])) {
$uuid = $_COOKIE['uuid'];
} else {
$uuid = CommonHelper::guid();
$domain = '.' . CommonHelper::getDomain();
setcookie('uuid', $uuid, time() + 63072000, '/', $domain);
}
$this->uuid = $uuid;
return $uuid;
}