service层基类

class BaseService
{

private static $_instance;

public function __construct()
{

}

/**
 * 实例化service
 * @author wzs
 * @return static
 */
final public static function service()
{
    $class = get_called_class();
    if (!isset(self::$_instance[$class]) || !(self::$_instance[$class] instanceof BaseService)) {
        self::$_instance[$class] = new static();
    }
    return self::$_instance[$class];
}

}