解决： failed to lazily initialize a collection of role: no session or session was closed问题

出现的异常为：org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: cn..domain.User.posts, no session or session was closed

failed to lazily initialize a collection of role: cn..domain.User.posts, no session or session was closed

at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:383)

at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:375)

at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:368)

at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:111)

at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:186)

at org.apache.struts2.util.MakeIterator.convert(MakeIterator.java:82)

at org.apache.struts2.components.IteratorComponent.start(IteratorComponent.java:270)

at org.apache.struts2.views.jsp.ComponentTagSupport.doStartTag(ComponentTagSupport.java:53)

at org.apache.jsp.WEB_002dINF.jsp.user.list_jsp._jspx_meth_s_005fiterator_005f1(list_jsp.java:325)

at org.apache.jsp.WEB_002dINF.jsp.user.list_jsp._jspx_meth_s_005fiterator_005f0(list_jsp.java:251)

at org.apache.jsp.WEB_002dINF.jsp.user.list_jsp._jspService(list_jsp.java:139)

at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)

at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)

at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)

at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)

at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436)

at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)

at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)

at org.apache.struts2.dispatcher.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:154)

at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:186)

at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:362)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:266)

at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165)

at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252)

at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)

at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)

at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)

at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:179)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:130)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)

at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:165)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:179)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)

at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)

at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)

at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:488)

at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)

at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)

at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:879)

at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:617)

at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1760)

at java.lang.Thread.run(Thread.java:619)

原因：是因为session已近关闭。。我们可以利用filter的形式解决

在web.xml配置文件中加filter

<filter>
<filter-name>OpenSessionInViewFilter</filter-name>
<filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>OpenSessionInViewFilter</filter-name>
<url-pattern>*.action</url-pattern>
</filter-mapping>

注意：这个filter必须在struts的核心过滤器之前。要不然不起作用