jpa缓存有一个很好的特性，即使用时不需要任何代码更改；仅需在persistence . xml文件中修改一些配置属性(比如缓存的大小和对象类型)。

A great feature of the JPA cache is that no coding change is necessary to use them; you just need some configuration properties (like size and object types to cache) in your persistence.xml file.

youdao

通过公共接口暴露引用类型，允许你的对象的用户，不用通过你已经定义的方法和属性就能修改它的内部。

Exposing reference types through your public interface allows users of your object to modify its internals without going through the methods and properties you've defined.

youdao