[简介](%E7%AE%80%E6%96%B9%E5%BC%8F%E7%9A%84%E6%96%B9%E5%BC%8F%E4%BB%8B.md) [饿汉式](%E9%A5%BF%E6%B1%89%E5%BC%8F.md) [懒汉式](%E6%87%92%E6%B1%89%E5%BC%8F.md) [静态内部方式](%E9%9D%99%E6%80%81%E5%86%85%E9%83%A8%E6%96%B9%E5%BC%8F.md) [枚举方式](%E6%9E%9A%E4%B8%BE%E6%96%B9%E5%BC%8F.md)