Spring托管事务,EclipseLink JPA,自定义隔离级别

Question

我怀疑这是令人尴尬的,我以一种可怕的方式做错了,但请耐心等待我.

我有一个Spring应用程序与Spring管理的事务.它使用EclipseLink JPA.我有一个方法,findByNativeQuery()后跟一个merge().我需要在真正的SERIAL事务隔离级别中实现这一点.我尝试添加 @Transactional(isolation=Isolation.SERIALIZABLE)

这不起作用,因为org.springframework.orm.jpa.vendor.EclipseLinkJpaDialect#beginTransaction 不支持任何事务隔离级别,但默认值.那么我尝试使用ElcipseLink的UnitOfWork内部并开始/编写我自己的事务,但后来我收到一个错误:

"java.lang.IllegalStateException : Not allowed to create transaction on shared EntityManager - use Spring transactions or EJB CMT instead

这当然有道理......但我该怎么办？

Answer 1

我试过这个,但我不完全确定解决方案.我从这个博客中获取了代码并将其改编为EclipseLink.这是代码:

package com.byteslounge.spring.tx.dialect;

import java.sql.SQLException;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceException;

import org.eclipse.persistence.sessions.UnitOfWork;
import org.springframework.orm.jpa.vendor.EclipseLinkJpaDialect;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.TransactionException;

public class CustomEclipseLinkJpaDialect extends EclipseLinkJpaDialect {

    private static final long serialVersionUID = 1L;

    private boolean lazyDatabaseTransaction = false;

    @Override
    public void setLazyDatabaseTransaction(boolean lazyDatabaseTransaction) {
        this.lazyDatabaseTransaction = lazyDatabaseTransaction;
    }

    @Override
    public Object beginTransaction(final EntityManager entityManager,
            final TransactionDefinition definition)
            throws PersistenceException, SQLException, TransactionException {

        UnitOfWork uow = (UnitOfWork) getSession(entityManager);
        uow.getLogin().setTransactionIsolation(definition.getIsolationLevel());

        entityManager.getTransaction().begin();
        if (!definition.isReadOnly() && !lazyDatabaseTransaction) {
            uow.beginEarlyTransaction();
        }

        return null;
    }
}

我发现事务启动时会记录SERIALIZABLE隔离,但需要对其进行正确测试以确认其有效.