java 如何在休眠/JPA 中禁用自动更新
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How to disable auto update in hibernate/JPA
提问by lutfijd
Is it possible to stop hibernate from auto updating a persistent object?
是否可以阻止休眠自动更新持久对象？
@Transactional
public ResultTO updateRecord(RequestTO requestTO) {
Entity entity = dao.getEntityById(requestTO.getId());
// now update the entity based on the data in the requestTO
ValidationResult validationResult = runValidation(entity);
if(validationResult.hasErrors()) {
// return ResultTO with validation errors
} else {
dao.persist(entity);
}
}
Here is what happens in the code, I retrieve the entity which would be considered by hibernate to be in persistent state, then I update some of the fields in the entity, then pass the entity to validation. if validation fails, then don't udpate, if validation succeeds then persist the entity.
这是代码中发生的事情，我检索了 hibernate 认为处于持久状态的实体，然后更新实体中的一些字段，然后将实体传递给验证。如果验证失败，则不要更新，如果验证成功则持久化实体。
Here is the main issue with this flow: because I updated the entity for it to be used in the validation, it does not matter whether I call persist() method (on the DAO) or not, the record will always be updated because hibernate detects that the entity has been changed and flags it for update.
这是此流程的主要问题：因为我更新了实体以便在验证中使用它，所以无论我是否调用 persist() 方法（在 DAO 上）都没有关系，记录将始终更新，因为休眠检测到实体已更改并将其标记为更新。
Keep im mind I can change the way i do validation and work around the issue, so I'm not interested in workarounds. I'm interested in knowing how i would be able to disable the hibernate feature where it automatically updates persistent objects.
请记住，我可以改变验证和解决问题的方式，所以我对解决方法不感兴趣。我很想知道如何禁用休眠功能，它会自动更新持久对象。
Please keep in mind I'm using hibernates' implementation of JPA. so Hibernate specific answers dealing with hibernate specific API will not work for me.
请记住，我正在使用 Hibernates 的 JPA 实现。因此，处理特定于 Hibernate 的 API 的 Hibernate 特定答案对我不起作用。
I tried to look for hibernate configuration and see if I can set any configuration to stop this behavior but no luck.
我试图寻找休眠配置，看看我是否可以设置任何配置来阻止这种行为，但没有运气。
Thanks
谢谢
--EDIT --- I couldn't find a solution to this, so I opted to rolling back the transaction without throwing any RuntimeException even though I'm in a declarative transaction using:
--EDIT --- 我找不到解决方案，所以我选择回滚事务而不抛出任何 RuntimeException 即使我在声明性事务中使用：
TransactionInterceptor.currentTransactionStatus().setRollbackOnly();
TransactionInterceptor.currentTransactionStatus().setRollbackOnly();
which works like a charm.
这就像一个魅力。
回答by ?ukasz Rzeszotarski
Configure FlushMode for your session.
为您的会话配置 FlushMode。
http://docs.jboss.org/hibernate/orm/3.5/api/org/hibernate/FlushMode.html
http://docs.jboss.org/hibernate/orm/3.5/api/org/hibernate/FlushMode.html
回答by Alex Kartishev
You can use EntityManager.clear() method after getting object from database. http://docs.oracle.com/javaee/6/api/javax/persistence/EntityManager.html#clear()
从数据库中获取对象后，您可以使用 EntityManager.clear() 方法。 http://docs.oracle.com/javaee/6/api/javax/persistence/EntityManager.html#clear()
回答by Bartun
You can call the following code:
您可以调用以下代码：
TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();
回答by calvinkrishy
Throw an exception if validation fails and have the caller handle that.
如果验证失败并让调用者处理该异常，则抛出异常。
