在Glassfish服务器上，我是使用JPA注入的新手：当我尝试查询数据库（检索公司对象的完整列表）时，我收到以下错误：
2015-08-08T23:21:43.810+0200|Grave: Error Rendering View[/secure/searchCompany.xhtml]
javax.el.ELException: /secure/searchCompany.xhtml @38,59 value="#{searchCompanyBean.companies}": java.lang.NullPointerException
at com.sun.faces.facelets.el.TagValueExpression.getValue(Unknown Source)
at javax.faces.component.ComponentStateHelper.eval(Unknown Source)
at javax.faces.component.ComponentStateHelper.eval(Unknown Source)
at org.richfaces.component.UISequence.getValue(UISequence.java:179)
at org.richfaces.component.UISequence.createExtendedDataModel(UISequence.java:113)
at org.richfaces.component.UIDataTableBase.createExtendedDataModel(UIDataTableBase.java:211)
at org.richfaces.component.UIDataAdaptor.getExtendedDataModel(UIDataAdaptor.java:467)
at org.richfaces.component.UIDataAdaptor.setRowKey(UIDataAdaptor.java:280)
at org.richfaces.renderkit.ExtendedDataTableRenderer.doEncodeChildren(ExtendedDataTableRenderer.java:720)
at org.richfaces.renderkit.RendererBase.encodeChildren(RendererBase.java:158)
at javax.faces.component.UIComponentBase.encodeChildren(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at org.richfaces.renderkit.RendererBase.renderChildren(RendererBase.java:282)
at org.richfaces.renderkit.html.PanelRenderer.doEncodeEnd(PanelRenderer.java:183)
at org.richfaces.renderkit.RendererBase.encodeEnd(RendererBase.java:180)
at javax.faces.component.UIComponentBase.encodeEnd(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at javax.faces.render.Renderer.encodeChildren(Unknown Source)
at javax.faces.component.UIComponentBase.encodeChildren(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(Unknown Source)
at com.sun.faces.application.view.MultiViewHandler.renderView(Unknown Source)
at javax.faces.application.ViewHandlerWrapper.renderView(Unknown Source)
at javax.faces.application.ViewHandlerWrapper.renderView(Unknown Source)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(Unknown Source)
at com.sun.faces.lifecycle.Phase.doPhase(Unknown Source)
at com.sun.faces.lifecycle.LifecycleImpl.render(Unknown Source)
at javax.faces.webapp.FacesServlet.service(Unknown Source)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:357)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:260)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:188)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
at java.lang.Thread.run(Thread.java:745)
Caused by: javax.el.ELException: java.lang.NullPointerException
at javax.el.BeanELResolver.getValue(BeanELResolver.java:368)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(Unknown Source)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(Unknown Source)
at com.sun.el.parser.AstValue.getValue(AstValue.java:140)
at com.sun.el.parser.AstValue.getValue(AstValue.java:204)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:226)
at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:50)
... 57 more
Caused by: java.lang.NullPointerException
at com.sdzee.dao.CompanyDao.searchCompanies(CompanyDao.java:30)
at com.sdzee.bean.SearchCompanyBean.getCompanies(SearchCompanyBean.java:104)
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:606)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:363)
... 63 more
2015-08-08T23:21:43.813+0200|Infos: Exception when handling error trying to reset the response.
java.lang.NullPointerException
at com.sdzee.dao.CompanyDao.searchCompanies(CompanyDao.java:30)
at com.sdzee.bean.SearchCompanyBean.getCompanies(SearchCompanyBean.java:104)
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:606)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:363)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(Unknown Source)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(Unknown Source)
at com.sun.el.parser.AstValue.getValue(AstValue.java:140)
at com.sun.el.parser.AstValue.getValue(AstValue.java:204)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:226)
at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:50)
at com.sun.faces.facelets.el.TagValueExpression.getValue(Unknown Source)
at javax.faces.component.ComponentStateHelper.eval(Unknown Source)
at javax.faces.component.ComponentStateHelper.eval(Unknown Source)
at org.richfaces.component.UISequence.getValue(UISequence.java:179)
at org.richfaces.component.UISequence.createExtendedDataModel(UISequence.java:113)
at org.richfaces.component.UIDataTableBase.createExtendedDataModel(UIDataTableBase.java:211)
at org.richfaces.component.UIDataAdaptor.getExtendedDataModel(UIDataAdaptor.java:467)
at org.richfaces.component.UIDataAdaptor.setRowKey(UIDataAdaptor.java:280)
at org.richfaces.renderkit.ExtendedDataTableRenderer.doEncodeChildren(ExtendedDataTableRenderer.java:720)
at org.richfaces.renderkit.RendererBase.encodeChildren(RendererBase.java:158)
at javax.faces.component.UIComponentBase.encodeChildren(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at org.richfaces.renderkit.RendererBase.renderChildren(RendererBase.java:282)
at org.richfaces.renderkit.html.PanelRenderer.doEncodeEnd(PanelRenderer.java:183)
at org.richfaces.renderkit.RendererBase.encodeEnd(RendererBase.java:180)
at javax.faces.component.UIComponentBase.encodeEnd(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at javax.faces.render.Renderer.encodeChildren(Unknown Source)
at javax.faces.component.UIComponentBase.encodeChildren(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(Unknown Source)
at com.sun.faces.application.view.MultiViewHandler.renderView(Unknown Source)
at javax.faces.application.ViewHandlerWrapper.renderView(Unknown Source)
at javax.faces.application.ViewHandlerWrapper.renderView(Unknown Source)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(Unknown Source)
at com.sun.faces.lifecycle.Phase.doPhase(Unknown Source)
at com.sun.faces.lifecycle.LifecycleImpl.render(Unknown Source)
at javax.faces.webapp.FacesServlet.service(Unknown Source)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:357)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:260)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:188)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
at java.lang.Thread.run(Thread.java:745)
2015-08-08T23:21:43.814+0200|Avertissement: StandardWrapperValve[Faces Servlet]: Servlet.service() for servlet Faces Servlet threw exception
java.lang.NullPointerException
at com.sdzee.dao.CompanyDao.searchCompanies(CompanyDao.java:30)
at com.sdzee.bean.SearchCompanyBean.getCompanies(SearchCompanyBean.java:104)
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:606)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:363)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(Unknown Source)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(Unknown Source)
at com.sun.el.parser.AstValue.getValue(AstValue.java:140)
at com.sun.el.parser.AstValue.getValue(AstValue.java:204)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:226)
at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:50)
at com.sun.faces.facelets.el.TagValueExpression.getValue(Unknown Source)
at javax.faces.component.ComponentStateHelper.eval(Unknown Source)
at javax.faces.component.ComponentStateHelper.eval(Unknown Source)
at org.richfaces.component.UISequence.getValue(UISequence.java:179)
at org.richfaces.component.UISequence.createExtendedDataModel(UISequence.java:113)
at org.richfaces.component.UIDataTableBase.createExtendedDataModel(UIDataTableBase.java:211)
at org.richfaces.component.UIDataAdaptor.getExtendedDataModel(UIDataAdaptor.java:467)
at org.richfaces.component.UIDataAdaptor.setRowKey(UIDataAdaptor.java:280)
at org.richfaces.renderkit.ExtendedDataTableRenderer.doEncodeChildren(ExtendedDataTableRenderer.java:720)
at org.richfaces.renderkit.RendererBase.encodeChildren(RendererBase.java:158)
at javax.faces.component.UIComponentBase.encodeChildren(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at org.richfaces.renderkit.RendererBase.renderChildren(RendererBase.java:282)
at org.richfaces.renderkit.html.PanelRenderer.doEncodeEnd(PanelRenderer.java:183)
at org.richfaces.renderkit.RendererBase.encodeEnd(RendererBase.java:180)
at javax.faces.component.UIComponentBase.encodeEnd(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at javax.faces.render.Renderer.encodeChildren(Unknown Source)
at javax.faces.component.UIComponentBase.encodeChildren(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at javax.faces.component.UIComponent.encodeAll(Unknown Source)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(Unknown Source)
at com.sun.faces.application.view.MultiViewHandler.renderView(Unknown Source)
at javax.faces.application.ViewHandlerWrapper.renderView(Unknown Source)
at javax.faces.application.ViewHandlerWrapper.renderView(Unknown Source)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(Unknown Source)
at com.sun.faces.lifecycle.Phase.doPhase(Unknown Source)
at com.sun.faces.lifecycle.LifecycleImpl.render(Unknown Source)
at javax.faces.webapp.FacesServlet.service(Unknown Source)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:357)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:260)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:188)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
at java.lang.Thread.run(Thread.java:745)
在CompanyDao.java文件中，第30行是：
Query requete = em.createQuery( JPQL_SEARCH_COMPANIES );
CompanyDao.java文件包含：
@Stateless
public class CompanyDao {
private static final String JPQL_SEARCH_COMPANIES = "SELECT c FROM Company c where c.name like :companyName and c.city like :companyCity";
private static final String PARAM_COMPANY_NAME = "companyName";
private static final String PARAM_COMPANY_CITY = "companyCity";
// Injection of the manager, which manages the connexion with the Database
@PersistenceContext( unitName = "bdd_sdzee_PU" )
private EntityManager em;
// Search all the companies
public List<Company> searchCompanies(String companyName, String companyCity) throws DAOException {
List<Company> listCompanies = null;
Query requete = em.createQuery( JPQL_SEARCH_COMPANIES );
requete.setParameter( PARAM_COMPANY_NAME, "%"+companyName+"%");
requete.setParameter( PARAM_COMPANY_CITY, "%"+companyCity+"%");
try {
listCompanies = requete.getResultList();
} catch ( NoResultException e ) {
return null;
} catch ( Exception e ) {
throw new DAOException( e );
}
return listCompanies;
}
}
searchCompany.xhtml文件：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<ui:composition template="/resources/template/layout.xhtml"
xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:p="http://primefaces.org/ui"
xmlns:a4j="http://richfaces.org/a4j"
xmlns:rich="http://richfaces.org/rich"
xmlns:fn="http://java.sun.com/jsp/jstl/functions">
<ui:define name="content">
<style type="text/css">
.rf-edt-r-sel{
font-weight: normal;
background-color: rgb(95,180,251);
}
</style>
<h:form>
<rich:panel style="width:1024px">
<h:panelGrid columns="5" border="0" cellpadding="0" styleClass="panelGridCenter" columnClasses="columnDefaultClass, columnDefaultClass, column200Class, columnDefaultClass, columnDefaultClass">
<h:outputText value="#{msg['company']} : " for="companyName" style="text-align:right"/>
<rich:autocomplete value="#{searchCompanyBean.companyName}" id="companyName" mode="lazyClient" autocompleteList="#{searchCompanyBean.listOfCompanyNames}" style="vertical-align: middle"/>
<h:outputText />
<h:outputText value="#{msg['city']} : " for="companyCity" style="text-align:right"/>
<rich:autocomplete value="#{searchCompanyBean.companyCity}" id="companyCity" mode="lazyClient" autocompleteList="#{searchCompanyBean.listOfCompanyCities}" style="vertical-align: middle" />
</h:panelGrid>
<h:panelGroup style="display:block; text-align:center">
<a4j:commandButton value="#{msg['search']}" action="#{searchCompanyBean.searchCompanies}" render="@form" execute="@form" />
</h:panelGroup>
</rich:panel>
<rich:panel style="width:1024px">
<rich:extendedDataTable id="table"
value="#{searchCompanyBean.companies}"
var="company" frozenColumns="1"
sortPriority="#{sortCompanyBean.sortPriorities}"
selectionMode="multiple"
style="height:500px; width:1000px;"
selection="#{searchCompanyBean.selectionCompanies}">
<a4j:ajax execute="@form"
event="selectionchange"
listener="#{searchCompanyBean.selectionListener}"
render="details"/>
<rich:column width="150px"
sortBy="#{company.name}"
sortOrder="#{sortCompanyBean.sortsOrders['name']}"
sortType="custom"
headerClass="headerClass1">
<f:facet name="header">
<h:panelGrid columns="2">
<a4j:commandLink execute="@this" value="#{msg['name']}" render="table"
action="#{sortCompanyBean.sort}">
<f:param name="sortProperty" value="name"/>
</a4j:commandLink>
<h:graphicImage value="/resources/default/images/icons/arrow_up.png"
rendered="#{sortCompanyBean.sortsOrders['name']=='descending'}"/>
<h:graphicImage value="/resources/default/images/icons/arrow_down.png"
rendered="#{sortCompanyBean.sortsOrders['name']=='ascending'}"/>
</h:panelGrid>
</f:facet>
#{company.name}
</rich:column>
<rich:column width="500px"
sortBy="#{company.comment}"
sortOrder="#{sortCompanyBean.sortsOrders['comment']}"
sortType="custom"
headerClass="headerClass1">
<f:facet name="header">
<h:panelGrid columns="2">
<a4j:commandLink execute="@this" value="#{msg['comment']}" render="table"
action="#{sortCompanyBean.sort}">
<f:param name="sortProperty" value="comment"/>
</a4j:commandLink>
<h:graphicImage value="/resources/default/images/icons/arrow_up.png"
rendered="#{sortCompanyBean.sortsOrders['comment']=='descending'}"/>
<h:graphicImage value="/resources/default/images/icons/arrow_down.png"
rendered="#{sortCompanyBean.sortsOrders['comment']=='ascending'}"/>
</h:panelGrid>
</f:facet>
#{company.comment}
</rich:column>
</rich:extendedDataTable>
<rich:contextMenu target="table" mode="ajax">
<rich:menuItem
label="#{msg['edit']}"
actionListener="#{maPopup.ouvrir}"
mode="ajax"
icon="/resources/default/images/icons/edit_detail.png"/>
</rich:contextMenu>
</rich:panel>
<rich:messages />
</h:form>
</ui:define>
</ui:composition>
SearchCompanyBean是：
@ManagedBean
@RequestScoped
public class SearchCompanyBean implements Serializable {
private static final long serialVersionUID = 1L;
// Injection de notre EJB (Session Bean Stateless)
@EJB
private @Inject CompanyService das;
private CompanyDao companyDao = new CompanyDao();
private Company company;
private List<Company> companies;
private List<String> listOfCompanyNames = null;
private List<String> listOfCompanyCities = null;
private String companyName;
private String companyCity;
private String selectionMode = "multiple";
private Collection<Object> selection = null;
private List<Company> selectionCompanies = null;
private Company selectionCompany = new Company();
public void selectionListener(AjaxBehaviorEvent event) {
UIExtendedDataTable dataTable = (UIExtendedDataTable)event.getComponent();
selectionCompanies = new ArrayList<Company>();
Object originalKey = dataTable.getRowKey();
for (Object selectionKey : selection) {
dataTable.setRowKey(selectionKey);
// if (dataTable.isRowAvailable()) {
selectionCompanies.add((Company)dataTable.getRowData());
// }
}
dataTable.setRowKey(originalKey);
}
public Collection<Object> getSelection() {
return selection;
}
public void setSelection(Collection<Object> selection) {
this.selection = selection;
}
public Company getSelectionCompany() {
if (selectionCompanies == null || selectionCompanies.isEmpty()) {
return null;
}
return selectionCompanies.get(0);
}
public void setSelectionCompany(Company company) {
this.company = company;
}
public List<Company> getSelectionCompanies() {
return selectionCompanies;
}
public void setSelectionCompanies(List<Company> selectionCompanies) {
this.selectionCompanies = selectionCompanies;
}
public void searchCompanies(){
companies = companyDao.searchCompanies(companyName, companyCity);
}
public Company getCompany(){
return company;
}
public List<Company> getCompanies(){
if (companies==null){
companies = companyDao.searchCompanies("",""); // By default, when displaying the page, all the Companies are listed
}
return companies;
}
}
persistence.xml文件是：
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="bdd_sdzee_PU" transaction-type="JTA">
<jta-data-source>jdbc/mysql_resource</jta-data-source>
<class>com.sdzee.entities.Utilisateur</class>
<class>com.sdzee.entities.Company</class>
<properties>
<property name="eclipselink.ddl-generation" value="create-tables"/>
<property name="eclipselink.logging.level.sql" value="FINEST"/>
<property name="eclipselink.logging.parameters" value="true"/>
</properties>
</persistence-unit>
</persistence>
感谢您的帮助。
答案 0 :(得分：2)
如果您的帖子包含完整的CompanyDao类，则会出现以下错误
java.lang.NullPointerException
at com.sdzee.dao.CompanyDao.searchCompanies(CompanyDao.java:30)
是因为您在忘记初始化时使用em变量。
Query requete = em.createQuery( JPQL_SEARCH_COMPANIES ); // Error --> "em" still null
答案 1 :(得分：0)
在SearchCompanyBean中，您可以创建自己的CompanyDao对象：
private CompanyDao companyDao = new CompanyDao();
但是，在这种情况下，不会发生字段注入，因为容器不知道它们（如PersistenceContext）。
因此，为了启用注入，您必须在SearchCompanyBean中注入CompanyDao，以使容器处理对象和依赖项的生命周期（就像您使用CompanyService一样）。