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如何在Glassfish 2.1的JPA中实现悲观锁定?

java-ee-5 glassfish locking jpa java

0

jsight TaherT · 技术社区 · 16 年前

当尝试设置锁(悲观)时,使用以下代码:

em.lock(controlnumbers, LockModeType.WRITE);
em.refresh(controlnumbers);

我得到了以下例外:

[#|2009-09-10T15:42:48.324-0400|INFO|sun-appserver2.1|javax.enterprise.system.container.ejb|_ThreadID=31;_ThreadName=httpSSLWorkerThread-8080-19;|
javax.ejb.TransactionRolledbackLocalException: Exception thrown from bean; nested exception is: javax.persistence.PersistenceException: ejb30-wrong-lock_called_without_version_locking-index (There is no English translation for this message.)
javax.persistence.PersistenceException: ejb30-wrong-lock_called_without_version_locking-index (There is no English translation for this message.)
        at oracle.toplink.essentials.internal.ejb.cmp3.base.EntityManagerImpl.lock(EntityManagerImpl.java:619)
        at com.sun.enterprise.util.EntityManagerWrapper.lock(EntityManagerWrapper.java:582)
        at com.eximtechnologies.transactionserver.persistence.session.ControlNumbersFacade.lock(ControlNumbersFacade.java:43)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

如何在Glassfish 2.1中实现悲观锁定?

2 回复 | 直到 16 年前

1

2

jsight TaherT 16 年前

有一种特定于Toplink Essentials(GF 2.1默认)的方法可以做到这一点:

public MyObject lock (MyObject controlnumbers) {
    String qStr = "select object(o) from MyObject as o where o.pk = :pk";
    Query q = em.createQuery(qStr);
    q.setParameter("pk", "a");
    q.setHint("toplink.pessimistic-lock", "Lock");
    controlnumbers = (MyObject)q.getSingleResult();
    return controlnumbers;
}

2

0

Jan 16 年前

http://en.wikibooks.org/wiki/Java_Persistence/Locking#Timestamp_Locking

问候,简