[单例模式](%E5%8D%95%E4%BE%8B%E6%A8%A1%E5%BC%8F.md) [适配器模式](%E9%80%82%E9%85%8D%E5%99%A8%E6%A8%A1%E5%BC%8F.md) [工厂模式](%E5%B7%A5%E5%8E%82%E6%A8%A1%E5%BC%8F.md) [观察者模式](%E8%A7%82%E5%AF%9F%E8%80%85%E6%A8%A1%E5%BC%8F.md)