/**
* 用户缓存管理单例
*
* @access public
* @param void
* @return Memcache 单例对象
*/
private static function getCacheInstance()
{
$get_instance = self::$cache_instance;
if (is_null(self::$cache_instance)) {
self::$cache_instance = MemcacheManager::instance();
}
return self::$cache_instance;
}