我有一个需要保存的UserProfile实体。将实体保存在数据库中后，出现以下异常：

Could not commit Hibernate transaction; nested exception is org.hibernate.TransactionException: Transaction not successfully started

另外，当我看到该表时，该实体将保留而不是进行回滚！

@Transactional(isolation=Isolation.REPEATABLE_READ)
public class HibernateUserProfileDAO implements UserProfileDAO {
    private org.hibernate.SessionFactory sessionFactory;
    public UserProfile getUserProfile(int userId) {
        org.hibernate.classic.Session session = sessionFactory.getCurrentSession();
        session.beginTransaction();
        UserProfile userProfile = new UserProfile();
        userProfile.setUserName("sury1");
        session.save(userProfile);
        session.getTransaction().commit();
        session.close();
        return userProfile;
    }
}

我正在使用hibernate事务管理器

<bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory"/>
</bean>

而我的hibernate配置是：

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
    <property name="dataSource" ref="dataSource"/>
    <property name="packagesToScan" value="com.springheatmvn.domain"/>
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.connection.pool_size">10</prop>
            <prop key="hibernate.connection.show_sql">true</prop>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
            <prop key="hibernate.hbm2ddl.auto">update</prop>
        </props>
    </property>     
</bean>

任何人都可以。告诉我这是怎么回事？