Java 休眠持久性异常
例外情况:Java 休眠持久性异常,java,hibernate,spring-mvc,Java,Hibernate,Spring Mvc,例外情况: A a =//get a from data base using hibernate by id //a contains b also a.setId(null); entityDao.persist(a);//line at which i am getting exception 使用“合并”而不是“持久化”时,一切正常。但是我想知道“持久化”有什么问题?当您设置主键时,您正在使对象分离,因此,在持久化分离的对象之前,您必须首先重新连接对象,而merge会这样做 A a =
A a =//get a from data base using hibernate by id
//a contains b also
a.setId(null);
entityDao.persist(a);//line at which i am getting exception
使用“合并”而不是“持久化”时,一切正常。但是我想知道“持久化”有什么问题?当您设置主键时,您正在使对象分离,因此,在持久化分离的对象之前,您必须首先重新连接对象,而merge会这样做
A a =//get a from data base using hibernate by id
//a contains b also
a.setId(null);
entityDao.persist(a);//line at which i am getting exception
Caused by: javax.persistence.PersistenceException: org.hibernate.PersistentObjectException: detached entity passed to persist: B