参考解决办法:
Before an entity removed, this entity must be manage state. We can use some of the functionmerge
,find
, etc. Note : After EntityManager
is closed, all the entities of its will be detached.
public void remove(Person p) {
Perosn p2 = em.merge(p);
em.remove(p2);
}
删除以前,必须是manage 状态,可以使用find 或者 merge 函数,将他变为manage状态。
JPA的生命周期介绍,参考: http://evil850209.iteye.com/blog/1932070