~~~ 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. 實現簡單，枚舉本身就是單例模式，由jvm從根本上提供保障，避免通過反射和反序列化的漏洞 2. 缺點時沒有延遲加載 ```