[单例定义](%E5%8D%95%E4%BE%8B%E5%AE%9A%E4%B9%89.md) [单例实现方式](%E5%8D%95%E4%BE%8B%E5%AE%9E%E7%8E%B0%E6%96%B9%E5%BC%8F.md) [单例破坏](%E5%8D%95%E4%BE%8B%E7%A0%B4%E5%9D%8F2.md)