Hibernate session FlushMode有五种属性:
1、NEVEL:已经废弃了,被MANUAL取代了
2 MANUAL:
如果FlushMode是MANUAL或NEVEL,在操作过程中hibernate会将事务设置为readonly,所以在增加、删除或修改操作过程中会出现如下错误
org.springframework.dao.InvalidDataAccessApiUsageException: Write operations are not allowed in read-only mode (FlushMode.NEVER) - turn your Session into FlushMode.AUTO or remove ‘readOnly‘ marker from transaction definition;
解决办法:配置事务,spring会读取事务中的各种配置来覆盖hibernate的session中的FlushMode;
3 AUTO
设置成auto之后,当程序进行查询、提交事务或者调用session.flush()的时候,都会使缓存和数据库进行同步,也就是刷新数据库
4 COMMIT
提交事务或者session.flush()时,刷新数据库;查询不刷新
5 ALWAYS:
每次进行查询、提交事务、session.flush()的时候都会刷数据库
ALWAYS和AUTO的区别:当hibernate缓存中的对象被改动之后,会被标记为脏数据(即与数据库不同步了)。当 session设置为FlushMode.AUTO时,hibernate在进行查询的时候会判断缓存中的数据是否为脏数据,是则刷数据库,不是则不刷,而always是直接刷新,不进行任何判断。很显然auto比always要高效得多。
参见hibernate的api说明https://www.hibernate.org/hib_docs/v3/api/org/hibernate/FlushMode.html
(二)
spring 环境下做一个check*操作时,抛出异常
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‘ marker from transaction definition.
后来发现,由于我在Action中调的方法名是checkXXXXX打头,而我的applicationContext.xml中的相关配置如下:
Xml代码
- <bean id="transactionInterceptor"
- class="org.springframework.transaction.interceptor.TransactionInterceptor">
- <property name="transactionManager" ref="transactionManager" />
- <property name="transactionAttributes">
- <props>
- <prop key="query*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="get*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="find*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="view*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="merge*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="check*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="insert*">
- PROPAGATION_REQUIRED,-GenericException
- </prop>
Xml代码
- <bean id="transactionInterceptor"
- class="org.springframework.transaction.interceptor.TransactionInterceptor">
- <property name="transactionManager" ref="transactionManager" />
- <property name="transactionAttributes">
- <props>
- <prop key="query*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="get*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="find*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="view*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="merge*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="check*">PROPAGATION_REQUIRED,readOnly</prop>
- <prop key="insert*">
- PROPAGATION_REQUIRED,-GenericException
- </prop>
即check打头的操作时,是不可操作数据库的,包括更新与增加数据。
找到原因后将
Xml代码
- <prop key="check*">PROPAGATION_REQUIRED,readOnly</prop>
Xml代码
- <prop key="check*">PROPAGATION_REQUIRED,readOnly</prop>
改为
Xml代码
- <prop key="check*">PROPAGATION_REQUIRED</prop>
Xml代码
- <prop key="check*">PROPAGATION_REQUIRED</prop>
后,重启服务,问题解决。
(三)
<aop:config proxy-target-class="true">
<aop:pointcut id="managerOperation" expression="execution(* com.yyii.eip..service.*Manager.*(..))"/>
<aop:advisor advice-ref="txAdvice" pointcut-ref="managerOperation"/>
</aop:config>
<!-- 基本事务定义 -->
<tx:advice id="txAdvice" transaction-manager="transactionManager">
<tx:attributes>
<tx:method name="save*"/>
<tx:method name="update*"/>
<tx:method name="remove*"/>
<tx:method name="delete*"/>
<tx:method name="create*"/>
<!-- other methods are set to read only -->
<tx:method name="*" read-only="true"/>
</tx:attributes>
</tx:advice>
如果把proxy-target-class="true"去掉, 不会报warn
但如果写上proxy-target-class="true", 2.0的配置依然会报WARN
修改web.xml中的]<param-value>false</param-value>为false试试!
<filter>
<filter-name>hibernateFilter</filter-name>
<filter-class>
org.springframework.orm.hibernate3.support.OpenSessionInViewFilter
</filter-class>
<init-param>
<param-name>singleSession</param-name>
<param-value>false</param-value> </init-param>
</filter>
<!-- 配置事务特性 -->
<tx:advice id="txAdvice" transaction-manager="transactionManager">
<tx:attributes>
<tx:method name="add*" propagation="REQUIRED"/>
<tx:method name="del*" propagation="REQUIRED"/>
<tx:method name="update*" propagation="REQUIRED"/>
<tx:method name="*" read-only="true"/>
</tx:attributes>
</tx:advice>
<!-- 配置那些类的方法进行事务管理 -->
<aop:config>
<aop:pointcut id="allManagerMethod" expression="execution (* com.landa.oa.manager.*.*(..))"/>
<aop:advisor advice-ref="txAdvice" pointcut-ref="allManagerMethod"/>
</aop:config>
<!--End_rbody_54519835//-->
Exceptions:
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‘ marker from transaction definition.
at org.springframework.orm.hibernate3.HibernateTemplate.checkWriteOperationAllowed(HibernateTemplate.java:1112)
at org.springframework.orm.hibernate3.HibernateTemplate$14.doInHibernate(HibernateTemplate.java:663)