问题:
EntityManager.merge()
can insert new objects and update existing ones. EntityManager.merge()
可以插入新对象并更新现有对象。
Why would one want to use persist()
(which can only create new objects)?为什么要使用persist()
(它只能创建新对象)?
解决方案:
参考一: https://stackoom.com/question/4ULw参考二: JPA EntityManager: Why use persist() over merge()?