/** * 创建唯一Cache实例 * @access public * @static * @return Object cacheLayerObject * @example $cacheLayer = cacheLayer::_getInstance() */ private static function _getInstance() { if (!self::$_instance instanceof cacheLayer) { self::$_instance = new self(); log::accessLog("Create cacheLayer instance success"); } log::returnLog(self::$_instance); return self::$_instance; }