Write operations are not allowed in read-only mode

错误代码:
  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
错误原因:
  OpenSessionInViewFilter在getSession的时候,会把获取回来的session的flush mode 设为FlushMode.NEVER。然后把该sessionFactory绑定到TransactionSynchronizationManager，使request的整个过程都使用同一个session，在请求过后再接除该sessionFactory的绑定，最后closeSessionIfNecessary根据该session是否已和transaction绑定来决定是否关闭session。在这个过程中，若HibernateTemplate 发现自当前session有不是readOnly的transaction，就会获取到FlushMode.AUTO Session，使方法拥有写权限。
也即是，如果有不是readOnly的transaction就可以由Flush.NEVER转为Flush.AUTO,拥有insert,update,delete操作权限，如果没有transaction，并且没有另外人为地设flush model的话，则doFilter的整个过程都是Flush.NEVER。所以受transaction保护的方法有写权限，没受保护的则没有。
解决办法:
  采用spring的事务声明,使方法受transaction控制

<!-- 配置事务拦截器--> 
    <bean id="transactionInterceptor" 
        class="org.springframework.transaction.interceptor.TransactionInterceptor"> 
        <!-- 事务拦截器bean需要依赖注入一个事务管理器 --> 
        <property name="transactionManager" ref="transactionManager" /> 
        <property name="transactionAttributes"> 
            <!-- 下面定义事务传播属性--> 
            <props> 
                 <prop key="get*">PROPAGATION_REQUIRED,readOnly</prop>
				 <prop key="find*">PROPAGATION_REQUIRED,readOnly</prop>	
				 <prop key="save*">PROPAGATION_REQUIRED</prop>
				 <prop key="add*">PROPAGATION_REQUIRED</prop>
				 <prop key="update*">PROPAGATION_REQUIRED</prop>
				 <prop key="edit*">PROPAGATION_REQUIRED</prop>
				 <prop key="delete*">PROPAGATION_REQUIRED</prop>
				 <prop key="write">PROPAGATION_REQUIRED,readOnly</prop>
            </props> 
        </property> 
    </bean> 

web.xml配置

  <filter>
	  <filter-name>openSessionInViewFilter</filter-name>
	  <!-- filter-class原来为org.springframework.orm.hibernate3.support.OpenSessionInViewFilter-->
	  <filter-class>com.ao.web.util.OpenSessionInViewFilter</filter-class>
      <init-param>   
            <param-name>singleSession</param-name>
            <param-value>true</param-value>   
      </init-param>
  </filter>

com.ao.web.util.OpenSessionInViewFilter代码

package com.ao.web.util;

import org.hibernate.FlushMode;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.dao.DataAccessResourceFailureException;
import org.springframework.orm.hibernate3.SessionFactoryUtils;


/**
 * @author Administrator
 *
 */
public class OpenSessionInViewFilter extends org.springframework.orm.hibernate3.support.OpenSessionInViewFilter {

	protected Session getSession(SessionFactory sessionFactory) throws DataAccessResourceFailureException {
		Session session = SessionFactoryUtils.getSession(sessionFactory, true);   
        FlushMode flushMode = session.getFlushMode();   
        if (flushMode != null) {   
        	session.setFlushMode(FlushMode.AUTO);//原来为  session.setFlushMode(flushMode);
        }   
        return session;
	}
	
	protected void closeSession(Session session, SessionFactory sessionFactory) {
		session.flush(); 
	    super.closeSession(session,sessionFactory); 
	}

}