~~~ public class Person { public static Person getInstance(){ return PersonEnum.INSTANCE.getInstance(); } private static enum PersonEnum{ INSTANCE; private Person person; private PersonEnum(){ person = new Person(); } public Person getInstance(){ return person; } } } ~~~ ``` 1. 实现简单，枚举本身就是单例模式，由jvm从根本上提供保障，避免通过反射和反序列化的漏洞 2. 缺点时没有延迟加载 ```