EntityManager em = _em; //acquired from OpenJPA
em.getTransaction().begin();
Connection conn;
try {
OpenJPAEntityManager oem = (OpenJPAEntityManager) em.getDelegate();
conn = oem.getConnection();
PreparedStatement ps = conn.prepareStatement(myStatement);
//initialize parameters in ps
ps.executeUpdate();
em.merge(myJpaObject);
em.getTransaction().commit();
} finally {
if (ps != null && !ps.isClosed()) {
ps.close();
}
if (em.getTransaction().isActive()) {
em.getTransaction().rollback();
}
}
谢谢！
解决方法
值得注意的是what the OpenJPA documentation has to say about it：
The returned connection is only guaranteed to be transactionally consistent with other EntityManager operations if the EntityManager is in a managed or non-optimistic transaction,if the EntityManager has flushed in the current transaction,or if you have used the OpenJPAEntityManager.beginStore method to ensure that a datastore transaction is in progress. Always close the returned connection before attempting any other EntityManager operations. OpenJPA will ensure that the underlying native connection is not released if a datastore transaction is in progress.
您的交易不受管理,但我认为这不是乐观的.此外,在启动事务和执行JDBC操作之间,您还没有完成任何JPA工作,因此我认为您可能属于“如果EntityManager在当前事务中已刷新”的情况.
你没有做的一件事就是在继续使用JPA之前关闭连接.我假设OpenJPA没有返回它正在使用的实际连接,但是在OpenJPA恢复工作之前应该关闭它的一些包装器.
