我有一个panelAdmin页面，当我点击adminList时，我转发参数
<h:commandLink value="Admini" action="#{userMB.adminList()}">
<f:param name="userId" value="#{loginMB.user.id}" />
</h:commandLink>
UserMB方法
public String adminList() {
return "adminList";
}
和faces-config：
<navigation-rule>
<from-view-id>/adminPanel.xhtml</from-view-id>
<navigation-case>
<from-outcome>adminList</from-outcome>
<to-view-id>/adminList.xhtml</to-view-id>
</navigation-case>
我的adminList页面：
<?xml version='1.0' encoding='UTF-8' ?>
<!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:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:p="http://primefaces.org/ui"
xmlns:c="http://java.sun.com/jsp/jstl/core">
<h:head>
<title>Lista adminow</title>
</h:head>
<h:body>
<h3>Zalogwano jako: #{loginMB.user.firstName} #{loginMB.user.firstName}</h3>
<h3>Lista administratorów</h3>
<f:view>
<h:form>
<p:dataTable value="#{userMB.allAdmins}" var="admin" widgetVar="customerTable">
<p:column headerText="Imie">
#{admin.firstName}
</p:column>
<p:column headerText="Nazwisko">
#{admin.lastName}
</p:column>
<p:column headerText="Pesel">
#{admin.personalId}
</p:column>
<p:column headerText="Edytuj">
<h:commandLink value="Edytuj" action="#{userMB.editStart()}">
<f:setPropertyActionListener target="#{userMB.user}" value="#{admin}" />
</h:commandLink>
</p:column>
<p:column headerText="Usun">
<h:commandLink value="Usun" action="#{userMB.deleteUser()}">
<f:setPropertyActionListener target="#{userMB.user}" value="#{admin}" />
</h:commandLink>
</p:column>
</p:dataTable>
<h:commandButton value="add" action="#{userMB.createStart()}"/>
<h:commandButton value="back" action="/adminPanel.xhtml"/>
</h:form>
</f:view>
</h:body>
</html>
当我点击添加按钮或后退按钮时出现错误：HTTP状态500
type Exception report
message
descriptionThe server encountered an internal error () that prevented it from fulfilling this request.
exception
javax.servlet.ServletException
root cause
java.lang.NullPointerException
note The full stack traces of the exception and its root causes are available in the GlassFish Server Open Source Edition 3.1.2.2 logs.
：
WARNING: StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception
java.lang.NullPointerException
at pl.ePrzychodnia.mb.UserMB.getAllAdmins(UserMB.java:51)
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 org.primefaces.component.datatable.DataTable.getValue(DataTable.java:729)
at org.primefaces.component.api.UIData.getDataModel(UIData.java:575)
at org.primefaces.component.api.UIData.setRowModel(UIData.java:405)
at org.primefaces.component.api.UIData.setRowIndex(UIData.java:397)
at org.primefaces.component.api.UIData.processPhase(UIData.java:254)
at org.primefaces.component.api.UIData.processDecodes(UIData.java:223)
at javax.faces.component.UIForm.processDecodes(UIForm.java:225)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIComponentBase.processDecodes(UIComponentBase.java:1176)
at javax.faces.component.UIViewRoot.processDecodes(UIViewRoot.java:933)
at com.sun.faces.lifecycle.ApplyRequestValuesPhase.execute(ApplyRequestValuesPhase.java:78)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
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)
UserMB
@ManagedBean
@RequestScoped
public class UserMB {
@EJB
private UserFacadeLocal userFacade;
private User user;
public List<User> getAllAdmins() {
return userFacade.findAllAdmins();
}
UserFacade
@Stateless
public class UserFacade implements UserFacadeLocal {
@PersistenceContext
private EntityManager em;
@EJB
private UserDao userDao;
@Override
public List<User> findAllAdmins() {
FacesContext context = FacesContext.getCurrentInstance();
Map requestParameterMap = (Map) context.getExternalContext().getRequestParameterMap();
String paramId = requestParameterMap.get("userId").toString();
Integer userId = Integer.parseInt(paramId);
Query q = em.createQuery("SELECT u FROM User u where u.role = 'admin' and u.id <> :id");
q.setParameter("id", userId);
List<User> users = q.getResultList();
return users;
}
答案 0 :(得分：0)
从堆栈跟踪看起来UserFacadeLocal没有注入UserMB。在getAllAdmins方法中放置一个断点并验证是否是这种情况。