请教spring 和hibernate结合使用的问题

系统采用spring 和hibernate结合开发，当应用部署到websphere后，发现当在dao中调用getHibernateTemplate().saveOrUpdate(model)时出现首次保存成功，第二次保存失败，第三次又保存成功，第四次又保存失败的情况，这种情况需要怎么解决呢？应用部署在tomcat上没有这个问题。

saveOrUpdate 之后要flush一下.
另外,注意model的关键属性,可能要先merge一下.
特别是从Browser下传过来的值.

最好把出错日志拿来.

如果说开发环境好tomcat, 应用环境(websphere)有问题.
检查一下有没有library冲突, 就是别的项目里跟你的项目的jar 文件冲突.

非常感谢您的回复，我在调用了saveorupdate后已经进行了flush操作；我的id是采用native这种生成策略；以下是报错信息：
[06-4-19 15:44:08:938 CST] 2e8829f6 WebGroup      E SRVE0026E: ［Servlet 错误］－［］：java.lang.NullPointerException
at oracle.jdbc.dbaccess.DBDataSetImpl.clearItem(DBDataSetImpl.java(Compiled Code))
at oracle.jdbc.driver.OraclePreparedStatement.clearParameters(OraclePreparedStatement.java:3401)
at com.ibm.ws.rsadapter.jdbc.WSJdbcConnection.resetStatement(WSJdbcConnection.java:1719)
at com.ibm.ws.rsadapter.jdbc.WSJdbcConnection.prepareStatement(WSJdbcConnection.java:1415)
at com.ibm.ws.rsadapter.jdbc.WSJdbcConnection.prepareStatement(WSJdbcConnection.java:1381)
at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:396)
at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:76)
at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:69)
at org.hibernate.jdbc.AbstractBatcher.prepareBatchStatement(AbstractBatcher.java:150)
at org.hibernate.persister.entity.BasicEntityPersister.update(BasicEntityPersister.java:1954)
at org.hibernate.persister.entity.BasicEntityPersister.updateOrInsert(BasicEntityPersister.java:1909)
at org.hibernate.persister.entity.BasicEntityPersister.update(BasicEntityPersister.java:2149)
at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:75)
at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:239)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:223)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:137)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:274)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:730)
at org.springframework.orm.hibernate3.HibernateTemplate$27.doInHibernate(HibernateTemplate.java:769)
at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java:356)
at org.springframework.orm.hibernate3.HibernateTemplate.flush(HibernateTemplate.java:767)

at sun.reflect.GeneratedMethodAccessor1390.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java(Compiled Code))
at java.lang.reflect.Method.invoke(Method.java(Compiled Code))
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:292)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:155)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:122)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:144)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:174)
at $Proxy126.saveLimitedPerson(Unknown Source)

at org.springframework.web.servlet.mvc.SimpleFormController.onSubmit(SimpleFormController.java:361)
at org.springframework.web.servlet.mvc.SimpleFormController.onSubmit(SimpleFormController.java:335)
at org.springframework.web.servlet.mvc.SimpleFormController.processFormSubmission(SimpleFormController.java:258)
at org.springframework.web.servlet.mvc.AbstractFormController.handleRequestInternal(AbstractFormController.java:245)
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:139)
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:44)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:684)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:625)
at org.springframework.web.servlet.FrameworkServlet.serviceWrapper(FrameworkServlet.java:386)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:355)
at javax.servlet.http.HttpServlet.service(HttpServlet.java(Compiled Code))
at javax.servlet.http.HttpServlet.service(HttpServlet.java(Compiled Code))
at com.ibm.ws.webcontainer.servlet.StrictServletInstance.doService(StrictServletInstance.java(Compiled Code))
at com.ibm.ws.webcontainer.servlet.StrictLifecycleServlet._service(StrictLifecycleServlet.java(Compiled Code))
at com.ibm.ws.webcontainer.servlet.IdleServletState.service(StrictLifecycleServlet.java(Compiled Code))
at com.ibm.ws.webcontainer.servlet.StrictLifecycleServlet.service(StrictLifecycleServlet.java(Inlined Compiled Code))
at com.ibm.ws.webcontainer.servlet.ServletInstance.service(ServletInstance.java(Compiled Code))
at com.ibm.ws.webcontainer.servlet.ValidServletReferenceState.dispatch(ValidServletReferenceState.java(Compiled Code))
at com.ibm.ws.webcontainer.servlet.ServletInstanceReference.dispatch(ServletInstanceReference.java(Inlined Compiled Code))
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java(Compiled Code))
at filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:169)
at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java(Compiled Code))
at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java(Compiled Code))
at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.handleWebAppDispatch(WebAppRequestDispatcher.java(Compiled Code))
at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.dispatch(WebAppRequestDispatcher.java(Compiled Code))
at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.forward(WebAppRequestDispatcher.java(Compiled Code))
at com.ibm.ws.webcontainer.srt.WebAppInvoker.doForward(WebAppInvoker.java(Compiled Code))
at com.ibm.ws.webcontainer.srt.WebAppInvoker.handleInvocationHook(WebAppInvoker.java(Compiled Code))
at com.ibm.ws.webcontainer.cache.invocation.CachedInvocation.handleInvocation(CachedInvocation.java(Compiled Code))
at com.ibm.ws.webcontainer.cache.invocation.CacheableInvocationContext.invoke(CacheableInvocationContext.java(Compiled Code))
at com.ibm.ws.webcontainer.srp.ServletRequestProcessor.dispatchByURI(ServletRequestProcessor.java(Compiled Code))
at com.ibm.ws.webcontainer.oselistener.OSEListenerDispatcher.service(OSEListener.java(Compiled Code))
at com.ibm.ws.webcontainer.http.HttpConnection.handleRequest(HttpConnection.java(Compiled Code))
at com.ibm.ws.http.HttpConnection.readAndHandleRequest(HttpConnection.java(Compiled Code))
at com.ibm.ws.http.HttpConnection.run(HttpConnection.java(Compiled Code))
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java(Compiled Code))