我是JPA和Hibernate的新手。我正在尝试编码SAVE方法我收到了这个错误:
springframework.transaction.TransactionSystemException:无法 提交JPA事务;嵌套异常是 javax.persistence.RollbackException:提交时出错 交易
代码:
@PersistenceContext
private EntityManager em;
@Override
@Transactional
public UserMeal save(UserMeal userMeal, int userId) {
User ref = em.getReference(User.class, userId);
userMeal.setUser(ref);
if (userMeal.isNew()) {
em.persist(userMeal);
return userMeal;
} else {
if (get(userMeal.getId(), userId) == null) return null;
return em.merge(userMeal);
} }