open Session in view出现错误的解决方法Write operations are not allowed in read-only mode (FlushMode.NEVER) -
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使用Spring提供的Open Session In View而引起Write operations are not allowed in read-only mode (FlushMode.NEVER) 错误解决：
在没有使用Spring提供的Open Session In View情况下，因需要在service(or Dao)层里把session关闭，所以lazy loading 为true的话，要在应用层内把关系集合都初始化，如 company.getEmployees()，否则Hibernate抛session already closed Exception; Open Session In View提供了一种简便的方法，较好地解决了lazy loading问题. 它有两种配置方式OpenSessionInViewInterceptor和OpenSessionInViewFilter(具体参看SpringSide)，功能相同，只是一个在web.xml配置，另一个在application.xml配置而已。Open Session In View在request把session绑定到当前thread期间一直保持hibernate session在open状态，使session在request的整个期间都可以使用，如在View层里PO也可以lazy loading数据，如 ${ company.employees }。当View 层逻辑完成后，才会通过Filter的doFilter方法或Interceptor的postHandle方法自动关闭session。 OpenSessionInViewInterceptor 配置 <beans> <bean name="openSessionInViewInterceptor" class="org.springframework.orm.hibernate3.support.OpenSessionInViewInterceptor"> <property name="sessionFactory" ref="sessionFactory"/></property> </bean> <bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> <property name="interceptors"> <list><ref bean="openSessionInViewInterceptor"/></list> </property> <property name="mappings"> </property> </bean> </beans> OpenSessionInViewFilter配置 <filter> <filter-name>hibernateFilter</filter-name> <filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class> <!-- singleSession默认为true,若设为false则等于没用OpenSessionInView --> <init-param> <param-name>singleSession</param-name> <param-value>true</param-value> </init-param> </filter> <filter-mapping> <filter-name>hibernateFilter</filter-name> <url-pattern>*.do</url-pattern> </filter-mapping> 很多人在使用OpenSessionInView过程中提及一个错误： 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 看看OpenSessionInViewFilter里的几个方法 protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,FilterChain filterChain) throws ServletException, IOException { SessionFactory sessionFactory = lookupSessionFactory(); logger.debug("Opening Hibernate Session in OpenSessionInViewFilter"); Session session = getSession(sessionFactory); TransactionSynchronizationManager.bindResource( sessionFactory, new SessionHolder(session)); try { filterChain.doFilter(request, response); } finally { TransactionSynchronizationManager.unbindResource(sessionFactory); logger.debug("Closing Hibernate Session in OpenSessionInViewFilter"); closeSession(session, sessionFactory); } } protected Session getSession(SessionFactory sessionFactory) throws DataAccessResourceFailureException { Session session = SessionFactoryUtils.getSession(sessionFactory, true); session.setFlushMode(FlushMode.NEVER); return session; } protected void closeSession(Session session, SessionFactory sessionFactory) throws CleanupFailureDataAccessException { SessionFactoryUtils.closeSessionIfNecessary(session, sessionFactory); } |