spring+hibernate更新问题

Question

<bean id="txManager"
class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory"></property>
</bean>
<aop:config>
         <aop:pointcut id="defaultDaoOperation"
    expression="execution(* com.test.*.dao.*(..))" />
         <aop:advisor advice-ref="defaultTxAdvice"
    pointcut-ref="defaultDaoOperation" />
</aop:config>
<tx:advice id="defaultTxAdvice" transaction-manager="txManager">
<tx:attributes>
<tx:method name="*"/>
</tx:attributes>
</tx:advice>无论是更新还是保存都出现下弥漫的错误:
org.springframework.dao.InvalidDataAccessApiUsageException: Write operations are not allowed in read-only mode (FlushMode.NEVER/MANUAL): Turn your Session into FlushMode.COMMIT/AUTO or remove 'readOnly' er from transaction definition.