/**
* 单例模型，获取实例的方法
* @return [Object] [redis操作对象的一个实例，该实例已经完成了连接操作]
*/
public static function getInstance()
{
if (!self::$_instance instanceof self) {
$conf = Registry::get('global_conf');
self::$_instance = new redis();
self::$_r = new Credis_Client($conf['redis_server_url'], $conf['redis_server_port']);
}
return self::$_instance;
}
