entityManager.persist(user)-> javax.persistence.EntityExistsException:User @ b3089已经是持久的 [英] entityManager.persist(user) -> javax.persistence.EntityExistsException: User@b3089 is already persistent

问题描述

// lookup existing user & set a currently null child entity (ContactInfo)
user.setContactInfo(contactInfo);

// update the user in the datastore with newly created child Entity             
entityManager.persist(user);

产生异常:

javax.persistence.EntityExistsException: User@b3089 is already persistent

由于用户已经存在，除了entityManager.persist之外，我还有其他方法可用于更新而不是插入吗?

Since the user already exists, is there some other method besides entityManager.persist that I should be using for an update instead of an insert?

推荐答案

您的user实例已经在持久性上下文中加载，只需对其进行修改，并且不要调用任何EntityManager方法，JPA提供程序将在刷新或提交时自动更新数据库.

Your user instance is already loaded in the persistence context, just modifiy it and don't invoke any EntityManager method, the JPA provider will automatically update the database at flush or commit time.

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