Hibernate session FlushMode

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 

1. <bean id="transactionInterceptor"  
2.         class="org.springframework.transaction.interceptor.TransactionInterceptor">  
3.         <property name="transactionManager" ref="transactionManager" />  
4.         <property name="transactionAttributes">  
5.             <props>  
6.                 <prop key="query*">PROPAGATION_REQUIRED,readOnly</prop>  
7.                 <prop key="get*">PROPAGATION_REQUIRED,readOnly</prop>  
8.                 <prop key="find*">PROPAGATION_REQUIRED,readOnly</prop>  
9.                 <prop key="view*">PROPAGATION_REQUIRED,readOnly</prop>                 
10.                 <prop key="merge*">PROPAGATION_REQUIRED,readOnly</prop>  
11.                 <prop key="check*">PROPAGATION_REQUIRED,readOnly</prop>  
12.                 <prop key="insert*">  
13.                     PROPAGATION_REQUIRED,-GenericException   
14.                 </prop>  

Xml代码  

1. <bean id="transactionInterceptor"  
2.         class="org.springframework.transaction.interceptor.TransactionInterceptor">  
3.         <property name="transactionManager" ref="transactionManager" />  
4.         <property name="transactionAttributes">  
5.             <props>  
6.                 <prop key="query*">PROPAGATION_REQUIRED,readOnly</prop>  
7.                 <prop key="get*">PROPAGATION_REQUIRED,readOnly</prop>  
8.                 <prop key="find*">PROPAGATION_REQUIRED,readOnly</prop>  
9.                 <prop key="view*">PROPAGATION_REQUIRED,readOnly</prop>                
10.                 <prop key="merge*">PROPAGATION_REQUIRED,readOnly</prop>  
11.                 <prop key="check*">PROPAGATION_REQUIRED,readOnly</prop>  
12.                 <prop key="insert*">  
13.                     PROPAGATION_REQUIRED,-GenericException  
14.                 </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 

1. <prop key="check*">PROPAGATION_REQUIRED,readOnly</prop>  

Xml代码  

1. <prop key="check*">PROPAGATION_REQUIRED,readOnly</prop>  

 改为

Xml代码 

1. <prop key="check*">PROPAGATION_REQUIRED</prop>  

Xml代码  

1. <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>

<!--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)