如何使用JPA释放锁定的行？
我正在使用 JPA 2.0 的 EclipseLink 实现，它允许悲观锁定。我知道如何锁定实体，但如何释放锁定？起初我以为这一切都是在事务中处理的（换句话说，实体被锁定，直到您提交事务），但情况似乎并非如此。
我尝试了快速谷歌搜索（似乎这应该很明显），但我没有找到任何东西......
I'm using the EclipseLink implementation of the JPA 2.0 which allows pessimistic locking. I know how to lock an entity but how do I release the lock? At first I thought this was all taken care of within a transaction (in other words, the entity is locked until you commit the transaction), but that does not seem to be the case.
I tried a quick google search (seems like this should be pretty obvious), but I haven't found anything...
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经过一些睡眠...并在早上做了一些更多的测试后，我相信我已经解决了我的问题。
因此，锁实际上是
在事务中处理的。但是，当我测试代码时，我能够使用 EntityManager.find(Class, key) 方法检索锁定的行（未指定锁定策略）。我错误地认为，通过在一行上加锁，该行将无法被读取，就这样。但是，我重新阅读了
PESSIMISTIC_READ和PESSIMISTIC_WRITE的 JPA 定义，并注意到了我的问题：锁不一定会阻止所有读取，它只是阻止另一个事务事务在行上放置
READ 或WRITE 锁。After getting some sleep... and doing some more testing in the morning, I believe I have figured out my problem.
So the lock is actually
taken care of within a transaction. However, when I was testing my code, I was able to retrieve a locked row using theEntityManager.find(Class, key)method (no locking strategy specified).I erroneously thought that by putting a lock on a row, the row could not be read, period. However, I reread the JPA definitions of
PESSIMISTIC_READandPESSIMISTIC_WRITEand noticed my problem:The lock doesn't necessarily prevent all reads, it just prevents another transaction from putting a
READ or WRITE lockon the row.