org.hibernate.HibernateException:如果没有活动事务,则get无效

Question

我是Hibernate的新手.

• 自动创建hibernate.cfg.xml(Netbeans向导)
• 自动创建HibernateUtil.java
• 自动创建带注释的POJO类

试图从数据库中获取对象但收到错误:

Exception in thread "pool-1-thread-1" org.hibernate.HibernateException: get is not valid without active transaction
    at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:297)

得到一个对象:

Session session = HibernateUtil.getSessionFactory().getCurrentSession();
CallInfo ci = (CallInfo) session.get(CallInfo.class, ucid);

的hibernate.cfg.xml

<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/sochi_feedback</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">root</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.query.factory_class">org.hibernate.hql.classic.ClassicQueryTranslatorFactory</property>
<property name="hibernate.current_session_context_class">thread</property>

Answer 1

加

Transaction tx = session.beginTransaction(); //此语句将启动事务

就在你之前 CallInfo ci = (CallInfo) session.get(CallInfo.class, ucid);

并在您的事务结束时通过调用提交更改..

tx.commit();

Answer 2

另一种解决方案是使用openSession()而不是getCurrentSession().然后,只有在更新查询时才需要使用事务.

Session session = HibernateUtil.getSessionFactory().openSession();
CallInfo ci = (CallInfo) session.get(CallInfo.class, ucid);