JSF：调用 @ViewScoped bean 中的方法时出现评估异常和 NPE
爪哇战士们！
我有这个托管 bean 来处理与 Rede（网络）实体相关的操作，称为 RedesBean（NetworksBean）。我有三个页面来插入新网络：redes/nova.xhtml (new.xhtml)，它基本上是一系列用于插入网络属性的输入字段和一个调用 cadastraNova() (createNew()) 方法的 commandButton验证输入并计算一些值。然后 cadastraNova() 方法返回到另一个页面 redes/confirma.xhtml (confirm.xhtml)，该页面显示每个属性的值和计算值，要求用户确认，然后调用另一个方法 cadastraRede() (createNetwork() ）通过 JPA 将网络持久保存到数据库。
当我使用 @RequestScoped 时，第二个和第三个视图之间的值不会保留。当我使用@SessionScoped时，值被保留，但我认为@SessionScoped-ing这有点太多了。因此，经过一番谷歌搜索后，我发现了这个 @ViewScoped 注释，我认为它非常适合我的情况。但问题是：在第一个视图 (redes/nova.xhtml) 中单击 commandButton 后，我得到一个 NullPointerExcetption，这是由 EvaluationException 引起的。 cadastraNova() 方法被调用，但无法评估 bean 属性值。相关代码发布如下：
RedesBean.java
package br.cefetmg.ccc.gerir.web;
// suppressed imports
/**
* Bean to manage network and subnetwork views
* @author Arthur Alkmim
*
*/
@ManagedBean(name="redes")
@ViewScoped
public class RedesBean implements Serializable{
@EJB
transient RedeDAO redeDAO;
private static final Logger logger = Logger.getLogger("br.cefetmg.ccc.gerir.web.RedesBean");
// attributes, suppressed
// getters and setters, suppressed
// the "broken" method
public String cadastraNova(){
logger.info("Method cadastraNova() successfully invoked");
// verifica se a rede não já existe
if(redeDAO.buscaPorId(ipBase) != null){
FacesContext.getCurrentInstance().addMessage("Rede já existente", new FacesMessage("Já existe uma rede com esse IP"));
return FacesContext.getCurrentInstance().getViewRoot().getViewId();
}
calculaAtributos();
// verifica se o range de lease é válido
if(!validaRange())
// volta para a página de cadastro
return FacesContext.getCurrentInstance().getViewRoot().getViewId();
return "/redes/confirma";
}
// other suppressed methods
}
redes/nova.xhtml
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:ccc="http://java.sun.com/jsf/composite/compz">
<ui:composition template="/resources/estilo/template.xhtml">
<f:loadBundle var="msg" basename="br.cefetmg.ccc.gerir.web.AppResources"/>
<ui:define name="title">Nova rede</ui:define>
<ui:define name="content">
<h:form id="form">
<h3>Principal</h3>
<h:panelGrid columns="2" id="principal">
<h:outputText value="Nome da rede" />
<h:inputText value="#{redes.nome}" id="nome" />
<h:outputText value="IP" />
<h:panelGroup id="ip">
<ccc:inputOneIP ip="#{redes.ipBase}" id="ipBase" />
/
<h:inputText value="#{redes.cidr}" size="2" id="cidr" validatorMessage="O CIDR deve estar entre 0 e 32">
<f:validateLongRange minimum="0" maximum="32"/>
</h:inputText>
</h:panelGroup>
</h:panelGrid>
<h3>Servidores</h3>
<h:panelGrid columns="2">
<h:outputText value="Router" />
<ccc:inputManyIP ip="#{redes.routers}" id="routers" />
<h:outputText value="DNS" />
<ccc:inputManyIP ip="#{redes.dns}" id="dns" />
<h:outputText value="Netbios" />
<ccc:inputManyIP ip="#{redes.netbios}" id="netbios" />
</h:panelGrid>
<h3>Lease</h3>
<h:panelGrid columns="2">
<h:outputText value="Tempo default" />
<h:inputText value="#{redes.leaseDefault}" id="leaseDefault">
<f:validateLongRange minimum="0" />
</h:inputText>
<h:outputText value="Tempo máximo" />
<h:inputText value="#{redes.leaseMax}" id="leaseMax">
<f:validateLongRange minimum="0" />
</h:inputText>
<h:outputText value="Início da faixa" />
<ccc:inputOneIP ip="#{redes.rangeMin}" id="rangeMin" />
<h:outputText value="Fim da faixa" />
<ccc:inputOneIP ip="#{redes.rangeMax}" id="rangeMax" />
</h:panelGrid>
<h:commandButton action="#{redes.cadastraNova}" value="Cadastra"/>
</h:form>
</ui:define>
</ui:composition>
</html>
redes/confirma.xhtml
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:ccc="http://java.sun.com/jsf/composite/compz">
<ui:composition template="/resources/estilo/template.xhtml">
<f:loadBundle var="msg" basename="br.cefetmg.ccc.gerir.web.AppResources"/>
<ui:define name="title">Nova rede</ui:define>
<ui:define name="content">
<h:form id="form">
Nome: <h:outputText value="#{redes.nome}" /><br />
<ccc:outputOneIP ip="#{redes.ipBase}" />/<h:outputText value="#{redes.cidr}" />
(<ccc:outputOneIP ip="#{redes.ipMin}" /> a <ccc:outputOneIP ip="#{redes.ipMax}" />)<br />
Broadcast em: <ccc:outputOneIP ip="#{redes.broadcast}" /> <br />
Máscara de rede: <ccc:outputOneIP ip="#{redes.netmask}" /><br />
Roteadores: <ccc:outputManyIP ip="#{redes.routers}" /><br />
Servidores de DNS: <ccc:outputManyIP ip="#{redes.dns}"/><br />
Servidores netbios: <ccc:outputManyIP ip="#{redes.netbios}"/><br />
Tempo de lease padrão: <h:outputText value="#{redes.leaseDefault}"/><br />
Tempo de lease máximo: <h:outputText value="#{redes.leaseMax}"/><br />
Range do lease: <ccc:outputOneIP ip="#{redes.rangeMin}" /> a <ccc:outputOneIP ip="#{redes.rangeMax}" /><br />
<br />
Estes dados estão corretos?
<h:commandButton action="#{redes.cadastraRede}" value="Sim" />
<h:commandButton action="#{redes.cancelaCadastro}" value="Não" />
</h:form>
</ui:define>
</ui:composition>
</html>
服务器日志
[#|2010-10-27T13:55:07.713-0200|INFO|glassfish3.0.1|br.cefetmg.ccc.gerir.web.RedesBean|_ThreadID=31;_ThreadName=Thread-1;|Method cadastraNova() successfully invoked|#]
[#|2010-10-27T13:55:07.713-0200|SEVERE|glassfish3.0.1|javax.enterprise.resource.webcontainer.jsf.application|_ThreadID=31;_ThreadName=Thread-1;|java.lang.NullPointerException
javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
at javax.faces.component.UICommand.broadcast(UICommand.java:311)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
at br.cefetmg.ccc.gerir.web.RedesBean.cadastraNova(RedesBean.java:231)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
... 32 more
|#]
[#|2010-10-27T13:55:07.714-0200|WARNING|glassfish3.0.1|javax.enterprise.resource.webcontainer.jsf.lifecycle|_ThreadID=31;_ThreadName=Thread-1;|#{redes.cadastraNova}: java.lang.NullPointerException
javax.faces.FacesException: #{redes.cadastraNova}: java.lang.NullPointerException
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:114)
at javax.faces.component.UICommand.broadcast(UICommand.java:311)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:662)
Caused by: javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
... 31 more
Caused by: java.lang.NullPointerException
at br.cefetmg.ccc.gerir.web.RedesBean.cadastraNova(RedesBean.java:231)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
... 32 more
|#]
[#|2010-10-27T13:55:07.715-0200|WARNING|glassfish3.0.1|javax.enterprise.system.container.web.com.sun.enterprise.web|_ThreadID=31;_ThreadName=Thread-1;|StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception
javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
at javax.faces.component.UICommand.broadcast(UICommand.java:311)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
at br.cefetmg.ccc.gerir.web.RedesBean.cadastraNova(RedesBean.java:231)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
... 32 more
|#]
[#|2010-10-27T13:55:07.715-0200|WARNING|glassfish3.0.1|javax.enterprise.system.container.web.com.sun.enterprise.web|_ThreadID=31;_ThreadName=http-thread-pool-8080-(2);|StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception
javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
at javax.faces.component.UICommand.broadcast(UICommand.java:311)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
at br.cefetmg.ccc.gerir.web.RedesBean.cadastraNova(RedesBean.java:231)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
... 32 more
|#]
[#|2010-10-27T13:55:07.715-0200|WARNING|glassfish3.0.1|javax.enterprise.system.container.web.com.sun.enterprise.web|_ThreadID=31;_ThreadName=http-thread-pool-8080-(2);|StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception
javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
at javax.faces.component.UICommand.broadcast(UICommand.java:311)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
at br.cefetmg.ccc.gerir.web.RedesBean.cadastraNova(RedesBean.java:231)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
... 32 more
|#]
因此，正如你们所看到的，该方法实际上是由日志第一行中的记录器输出调用的。当该方法评估可能未更新的属性时，该方法会失败。那么，如何修复呢？
fellow Java warriors!
I have this managed bean to handle the Rede (Network) entity related operations called RedesBean (NetworksBean). I have three pages to insert a new network: redes/nova.xhtml (new.xhtml), which is basically a series of input fields to insert the Network properties and a commandButton which invokes a cadastraNova() (createNew()) method which validates the input and calculates some values. The cadastraNova() method then returns to another page, redes/confirma.xhtml (confirm.xhtml) which shows the value of each property and the calculated values, asks for user confirmation and then invokes another method, cadastraRede() (createNetwork()) to persist the Network to database via JPA.
When I use @RequestScoped, the values are not preserved between the second and third views. When I use @SessionScoped, the values are preserved, but I think @SessionScoped-ing this is a bit too much. So, after a bit of Googling, I found this @ViewScoped annotation which I think fits perfectly to my case. But here's the issue: after I click the commandButton in the first view (redes/nova.xhtml), I get a NullPointerExcetption, caused by a EvaluationException. The cadastraNova() method is invoked, but it fails to evaluate the bean property values. The relevant code is posted below:
RedesBean.java
package br.cefetmg.ccc.gerir.web;
// suppressed imports
/**
* Bean to manage network and subnetwork views
* @author Arthur Alkmim
*
*/
@ManagedBean(name="redes")
@ViewScoped
public class RedesBean implements Serializable{
@EJB
transient RedeDAO redeDAO;
private static final Logger logger = Logger.getLogger("br.cefetmg.ccc.gerir.web.RedesBean");
// attributes, suppressed
// getters and setters, suppressed
// the "broken" method
public String cadastraNova(){
logger.info("Method cadastraNova() successfully invoked");
// verifica se a rede não já existe
if(redeDAO.buscaPorId(ipBase) != null){
FacesContext.getCurrentInstance().addMessage("Rede já existente", new FacesMessage("Já existe uma rede com esse IP"));
return FacesContext.getCurrentInstance().getViewRoot().getViewId();
}
calculaAtributos();
// verifica se o range de lease é válido
if(!validaRange())
// volta para a página de cadastro
return FacesContext.getCurrentInstance().getViewRoot().getViewId();
return "/redes/confirma";
}
// other suppressed methods
}
redes/nova.xhtml
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:ccc="http://java.sun.com/jsf/composite/compz">
<ui:composition template="/resources/estilo/template.xhtml">
<f:loadBundle var="msg" basename="br.cefetmg.ccc.gerir.web.AppResources"/>
<ui:define name="title">Nova rede</ui:define>
<ui:define name="content">
<h:form id="form">
<h3>Principal</h3>
<h:panelGrid columns="2" id="principal">
<h:outputText value="Nome da rede" />
<h:inputText value="#{redes.nome}" id="nome" />
<h:outputText value="IP" />
<h:panelGroup id="ip">
<ccc:inputOneIP ip="#{redes.ipBase}" id="ipBase" />
/
<h:inputText value="#{redes.cidr}" size="2" id="cidr" validatorMessage="O CIDR deve estar entre 0 e 32">
<f:validateLongRange minimum="0" maximum="32"/>
</h:inputText>
</h:panelGroup>
</h:panelGrid>
<h3>Servidores</h3>
<h:panelGrid columns="2">
<h:outputText value="Router" />
<ccc:inputManyIP ip="#{redes.routers}" id="routers" />
<h:outputText value="DNS" />
<ccc:inputManyIP ip="#{redes.dns}" id="dns" />
<h:outputText value="Netbios" />
<ccc:inputManyIP ip="#{redes.netbios}" id="netbios" />
</h:panelGrid>
<h3>Lease</h3>
<h:panelGrid columns="2">
<h:outputText value="Tempo default" />
<h:inputText value="#{redes.leaseDefault}" id="leaseDefault">
<f:validateLongRange minimum="0" />
</h:inputText>
<h:outputText value="Tempo máximo" />
<h:inputText value="#{redes.leaseMax}" id="leaseMax">
<f:validateLongRange minimum="0" />
</h:inputText>
<h:outputText value="Início da faixa" />
<ccc:inputOneIP ip="#{redes.rangeMin}" id="rangeMin" />
<h:outputText value="Fim da faixa" />
<ccc:inputOneIP ip="#{redes.rangeMax}" id="rangeMax" />
</h:panelGrid>
<h:commandButton action="#{redes.cadastraNova}" value="Cadastra"/>
</h:form>
</ui:define>
</ui:composition>
</html>
redes/confirma.xhtml
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:ccc="http://java.sun.com/jsf/composite/compz">
<ui:composition template="/resources/estilo/template.xhtml">
<f:loadBundle var="msg" basename="br.cefetmg.ccc.gerir.web.AppResources"/>
<ui:define name="title">Nova rede</ui:define>
<ui:define name="content">
<h:form id="form">
Nome: <h:outputText value="#{redes.nome}" /><br />
<ccc:outputOneIP ip="#{redes.ipBase}" />/<h:outputText value="#{redes.cidr}" />
(<ccc:outputOneIP ip="#{redes.ipMin}" /> a <ccc:outputOneIP ip="#{redes.ipMax}" />)<br />
Broadcast em: <ccc:outputOneIP ip="#{redes.broadcast}" /> <br />
Máscara de rede: <ccc:outputOneIP ip="#{redes.netmask}" /><br />
Roteadores: <ccc:outputManyIP ip="#{redes.routers}" /><br />
Servidores de DNS: <ccc:outputManyIP ip="#{redes.dns}"/><br />
Servidores netbios: <ccc:outputManyIP ip="#{redes.netbios}"/><br />
Tempo de lease padrão: <h:outputText value="#{redes.leaseDefault}"/><br />
Tempo de lease máximo: <h:outputText value="#{redes.leaseMax}"/><br />
Range do lease: <ccc:outputOneIP ip="#{redes.rangeMin}" /> a <ccc:outputOneIP ip="#{redes.rangeMax}" /><br />
<br />
Estes dados estão corretos?
<h:commandButton action="#{redes.cadastraRede}" value="Sim" />
<h:commandButton action="#{redes.cancelaCadastro}" value="Não" />
</h:form>
</ui:define>
</ui:composition>
</html>
The server log
[#|2010-10-27T13:55:07.713-0200|INFO|glassfish3.0.1|br.cefetmg.ccc.gerir.web.RedesBean|_ThreadID=31;_ThreadName=Thread-1;|Method cadastraNova() successfully invoked|#]
[#|2010-10-27T13:55:07.713-0200|SEVERE|glassfish3.0.1|javax.enterprise.resource.webcontainer.jsf.application|_ThreadID=31;_ThreadName=Thread-1;|java.lang.NullPointerException
javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
at javax.faces.component.UICommand.broadcast(UICommand.java:311)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
at br.cefetmg.ccc.gerir.web.RedesBean.cadastraNova(RedesBean.java:231)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
... 32 more
|#]
[#|2010-10-27T13:55:07.714-0200|WARNING|glassfish3.0.1|javax.enterprise.resource.webcontainer.jsf.lifecycle|_ThreadID=31;_ThreadName=Thread-1;|#{redes.cadastraNova}: java.lang.NullPointerException
javax.faces.FacesException: #{redes.cadastraNova}: java.lang.NullPointerException
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:114)
at javax.faces.component.UICommand.broadcast(UICommand.java:311)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:662)
Caused by: javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
... 31 more
Caused by: java.lang.NullPointerException
at br.cefetmg.ccc.gerir.web.RedesBean.cadastraNova(RedesBean.java:231)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
... 32 more
|#]
[#|2010-10-27T13:55:07.715-0200|WARNING|glassfish3.0.1|javax.enterprise.system.container.web.com.sun.enterprise.web|_ThreadID=31;_ThreadName=Thread-1;|StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception
javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
at javax.faces.component.UICommand.broadcast(UICommand.java:311)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
at br.cefetmg.ccc.gerir.web.RedesBean.cadastraNova(RedesBean.java:231)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
... 32 more
|#]
[#|2010-10-27T13:55:07.715-0200|WARNING|glassfish3.0.1|javax.enterprise.system.container.web.com.sun.enterprise.web|_ThreadID=31;_ThreadName=http-thread-pool-8080-(2);|StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception
javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
at javax.faces.component.UICommand.broadcast(UICommand.java:311)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
at br.cefetmg.ccc.gerir.web.RedesBean.cadastraNova(RedesBean.java:231)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
... 32 more
|#]
[#|2010-10-27T13:55:07.715-0200|WARNING|glassfish3.0.1|javax.enterprise.system.container.web.com.sun.enterprise.web|_ThreadID=31;_ThreadName=http-thread-pool-8080-(2);|StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception
javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
at javax.faces.component.UICommand.broadcast(UICommand.java:311)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
at br.cefetmg.ccc.gerir.web.RedesBean.cadastraNova(RedesBean.java:231)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
... 32 more
|#]
So, as you guys can see, the method is really being invoked by the logger output in the log first line. The method fails when it evaluates a property which is probably not being updated. So, how to fix?
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评论（2）
到目前为止，您所显示的方法片段中唯一可以为
null的是redeDAO。由于它被标记为瞬态，我认为服务器配置为立即将视图/会话存储在磁盘上（通过序列化），而不是始终保留在内存中。任何声明为瞬态的内容都将在序列化期间丢失，并且 JSF 无法在反序列化后为您重新注入它。我建议使
@EJB非瞬态（只需实现Serialized）并重试。The only which can be
nullin the method snippet you've shown as far isredeDAO. Since it's markedtransientI think that the server is configured to store views/sessions on disk immediately (by serialization) instead of being kept in memory all the time. Anything which is declaredtransientwill be lost during serialization and JSF can't reinject it for you after deserialization.I'd suggest to make the
@EJBnon-transient (just implementSerializable) and retry.有点解决了。我从 @ViewScoped 更改为 @ConversationScoped，并使用 CDI 注释而不是 JSF 注释 - 即，@Named 和 @Inject 而不是 @ManagedBean 和 @EJB。
Kind of solved it. I changed from @ViewScoped to @ConversationScoped and used CDI annotations instead of JSF ones - that is, @Named and @Inject instead of @ManagedBean and @EJB.