这是我的jsf文件
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core">
<h:head>
</h:head>
<h:body>
<f:view>
<h:form>
<h1><h:outputText value="List"/></h1>
<h:dataTable value="#{manageBean.tours}" var="item">
<h:column>
<f:facet name="header">
<h:outputText value="Tourid"/>
</f:facet>
<h:outputText value="#{item.tourid}"/>
</h:column>
</h:dataTable>
</h:form>
</f:view>
</h:body>
</html>
这是我的管理bean
public class manageBean {
private Tourpackage tour;
private List<Tourpackage> tours;
private sessionBean session;
public manageBean() {
}
public List<Tourpackage> getTours() {
return session.retrieveTour();
}
public void setTours(List<Tourpackage> tours) {
this.tours = tours;
}
}
这是我的会话bean
public class sessionBean {
private EntityManager em;
public List<Tourpackage> retrieveTour(){
Query query = em.createNamedQuery("Tourpackage.findAll");
return query.getResultList();
}
}
这是我的实体类(不包括变量和方法)
@NamedQueries({
@NamedQuery(name = "Reservation.findAll", query = "SELECT r FROM Reservation r"),
@NamedQuery(name = "Reservation.findByReservationid", query = "SELECT r FROM Reservation r WHERE r.reservationid = :reservationid"),
@NamedQuery(name = "Reservation.findByReservationdate", query = "SELECT r FROM Reservation r WHERE r.reservationdate = :reservationdate")})
公共类Reservation实现Serializable {
这里有人是JSF专家吗?每次我通过netbeans运行JSF文件时，我都得到空指针异常，我使用的数据库在netbeans中。请原谅我糟糕的格式。堆栈跟踪java.lang.NullPointerException
at manageBean.getTours(manageBean.java:23)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:363)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at com.sun.el.parser.AstValue.getValue(AstValue.java:138)
at com.sun.el.parser.AstValue.getValue(AstValue.java:183)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:224)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
at javax.faces.component.UIData.getValue(UIData.java:731)
at javax.faces.component.UIData.getDataModel(UIData.java:1798)
at javax.faces.component.UIData.setRowIndexWithoutRowStatePreserved(UIData.java:484)
at javax.faces.component.UIData.setRowIndex(UIData.java:473)
at com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(TableRenderer.java:81)
at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:820)
at javax.faces.component.UIData.encodeBegin(UIData.java:1118)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1755)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1757)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1550)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:757)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1056)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:229)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:722)
在应用了建议的解决方案之后，我有了新的问题:
com.sun.faces.mgbean.ManagedBeanCreationException: An error occurred performing resource injection on managed bean manage
at com.sun.faces.mgbean.BeanBuilder.injectResources(BeanBuilder.java:211)
at com.sun.faces.mgbean.BeanBuilder.build(BeanBuilder.java:103)
at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:409)
at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269)
at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:244)
at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:116)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at com.sun.el.parser.AstIdentifier.getValue(AstIdentifier.java:103)
at com.sun.el.parser.AstValue.getValue(AstValue.java:179)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:224)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
at javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
at javax.faces.component.UIData.getValue(UIData.java:731)
at javax.faces.component.UIData.getDataModel(UIData.java:1798)
at javax.faces.component.UIData.setRowIndexWithoutRowStatePreserved(UIData.java:484)
at javax.faces.component.UIData.setRowIndex(UIData.java:473)
at com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(TableRenderer.java:81)
at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:820)
at javax.faces.component.UIData.encodeBegin(UIData.java:1118)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1755)
at javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1757)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1550)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:757)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1056)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:229)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:722)
Caused by: com.sun.faces.spi.InjectionProviderException: com.sun.enterprise.container.common.spi.util.InjectionException: Exception attempting to inject Remote ejb-ref name=manage/tour,Remote 3.x interface =entities.Tourpackage,ejb-link=null,lookup=,mappedName=,jndi-name=entities.Tourpackage,refType=Session into class manage: Lookup failed for 'java:comp/env/manage/tour' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming}
at org.glassfish.faces.integration.GlassFishInjectionProvider.inject(GlassFishInjectionProvider.java:194)
at com.sun.faces.mgbean.BeanBuilder.injectResources(BeanBuilder.java:205)
... 56 more
Caused by: com.sun.enterprise.container.common.spi.util.InjectionException: Exception attempting to inject Remote ejb-ref name=manage/tour,Remote 3.x interface =entities.Tourpackage,ejb-link=null,lookup=,mappedName=,jndi-name=entities.Tourpackage,refType=Session into class manage: Lookup failed for 'java:comp/env/manage/tour' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming}
at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl._inject(InjectionManagerImpl.java:703)
at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl.inject(InjectionManagerImpl.java:470)
at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl.injectInstance(InjectionManagerImpl.java:171)
at org.glassfish.faces.integration.GlassFishInjectionProvider.inject(GlassFishInjectionProvider.java:184)
... 57 more
Caused by: javax.naming.NamingException: Lookup failed for 'java:comp/env/manage/tour' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [Root exception is javax.naming.NamingException: Exception resolving Ejb for 'Remote ejb-ref name=manage/tour,Remote 3.x interface =entities.Tourpackage,ejb-link=null,lookup=,mappedName=,jndi-name=entities.Tourpackage,refType=Session' . Actual (possibly internal) Remote JNDI name used for lookup is 'entities.Tourpackage#entities.Tourpackage' [Root exception is javax.naming.NamingException: Lookup failed for 'entities.Tourpackage#entities.Tourpackage' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [Root exception is javax.naming.NameNotFoundException: entities.Tourpackage#entities.Tourpackage not found]]]
at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:518)
at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:455)
at javax.naming.InitialContext.lookup(InitialContext.java:411)
at javax.naming.InitialContext.lookup(InitialContext.java:411)
at com.sun.enterprise.container.common.impl.util.InjectionManagerImpl._inject(InjectionManagerImpl.java:599)
... 60 more
Caused by: javax.naming.NamingException: Exception resolving Ejb for 'Remote ejb-ref name=manage/tour,Remote 3.x interface =entities.Tourpackage,ejb-link=null,lookup=,mappedName=,jndi-name=entities.Tourpackage,refType=Session' . Actual (possibly internal) Remote JNDI name used for lookup is 'entities.Tourpackage#entities.Tourpackage' [Root exception is javax.naming.NamingException: Lookup failed for 'entities.Tourpackage#entities.Tourpackage' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [Root exception is javax.naming.NameNotFoundException: entities.Tourpackage#entities.Tourpackage not found]]
at com.sun.ejb.EjbNamingReferenceManagerImpl.resolveEjbReference(EjbNamingReferenceManagerImpl.java:191)
at com.sun.enterprise.container.common.impl.ComponentEnvManagerImpl$EjbReferenceProxy.create(ComponentEnvManagerImpl.java:1109)
at com.sun.enterprise.naming.impl.GlassfishNamingManagerImpl.lookup(GlassfishNamingManagerImpl.java:776)
at com.sun.enterprise.naming.impl.GlassfishNamingManagerImpl.lookup(GlassfishNamingManagerImpl.java:744)
at com.sun.enterprise.naming.impl.JavaURLContext.lookup(JavaURLContext.java:169)
at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:498)
... 64 more
Caused by: javax.naming.NamingException: Lookup failed for 'entities.Tourpackage#entities.Tourpackage' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [Root exception is javax.naming.NameNotFoundException: entities.Tourpackage#entities.Tourpackage not found]
at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:518)
at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:455)
at javax.naming.InitialContext.lookup(InitialContext.java:411)
at javax.naming.InitialContext.lookup(InitialContext.java:411)
at com.sun.ejb.EjbNamingReferenceManagerImpl.resolveEjbReference(EjbNamingReferenceManagerImpl.java:186)
... 69 more
Caused by: javax.naming.NameNotFoundException: entities.Tourpackage#entities.Tourpackage not found
at com.sun.enterprise.naming.impl.TransientContext.doLookup(TransientContext.java:248)
at com.sun.enterprise.naming.impl.TransientContext.lookup(TransientContext.java:215)
at com.sun.enterprise.naming.impl.SerialContextProviderImpl.lookup(SerialContextProviderImpl.java:77)
at com.sun.enterprise.naming.impl.LocalSerialContextProviderImpl.lookup(LocalSerialContextProviderImpl.java:119)
at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:505)
... 73 more
管理bean中的
sessionBean session从未初始化。如果您在Java EE 6环境中，将其转换为EJB:
@Stateless
public class sessionBean {
@PersistenceContext(unitName = "yourPersistenceContextFileName")
private EntityManager em;
//...
}
然后将其作为受管bean中的EJB调用。此外，您应该在@PostConstruct方法中检索数据，而不是在getter方法中检索数据，因为getter方法可以被多次调用](为什么JSF多次调用getter):
@ManagedBean
@ViewScoped
public class manageBean {
@EJB
private sessionBean session;
private List<Tourpackage> tours;
@PostConstruct
public void init() {
tours = session.retrieveTour();
}
//plain getters/setters
}
您的代码中没有注释!你只是忘记把它们包括在你的文章中，或者它们在代码中丢失了?至少你必须将manageBean注释为@ManagedBean(或@Named @Statefull)，并将@Inject注释添加到你注入的对象(EntityManager和sessionBean)，否则容器将永远不会处理它们的生命周期(即为你实例化它们，所以你不会得到npe)
用@ManagedBean注释您的类或将它们添加到faces-config.xml中。如果您使用cdi，请使用@Named注释它们。否则你不能访问你的via表达式。
无关的
按照约定，Java类型名通常以大写字母开头:
manageBean -> manageBean
sessionBean -> sessionBean