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我正在尝试转换String to aModelo entity using the JSFConverter`。

我有这样的看法：

<h:outputText value="Modelo*: "/>
<p:selectOneMenu style="width: 300px" value="#{modeloBean.modelo.nome}" id="modelo" converter="modeloConverter">
    <f:selectItem itemLabel="Select One" itemValue="" />
    <f:selectItems value="#{modeloBean.listaModelo()}" var="modelo" itemLabel="#{modelo.nome}" itemValue="#{modelo}" />                                
</p:selectOneMenu>
<p:message for="modelo"/>

而这个Modelo实体：

@Entity
@Table(name = "MODELO")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "Modelo.findAll", query = "SELECT m FROM Modelo m"),
    @NamedQuery(name = "Modelo.findById", query = "SELECT m FROM Modelo m WHERE m.id = :id"),
    @NamedQuery(name = "Modelo.findByNome", query = "SELECT m FROM Modelo m WHERE m.nome = :nome")})
public class Modelo implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy= GenerationType.AUTO)
    @Column(name = "ID")
    private Integer id;
    @Size(max = 255)
    @Column(name = "NOME")
    private String nome;
    @OneToMany(mappedBy = "modeloId")
    private List<Dipositivo> dipositivoList;
    // with respectives getters and setters

我试图创建Converter如下：

@FacesConverter(value="modeloConverter", forClass=Modelo.class)
@SessionScoped
public class ModeloConverter implements Converter{

    @EJB
    private ModeloFacade modeloFacade = new ModeloFacade();

    @Override
    public Object getAsObject(FacesContext context, UIComponent component, String value) {
        if(value == null || value.isEmpty()) {
            return null;
        }
        try {
            Object o = modeloFacade.consultarPorId(Long.valueOf(value));
            return o;
        } catch (Exception e) {
            throw new ConverterException(new FacesMessage(String.format("Cannot convert %s to Modelo", value)), e);
        }
    }

    @Override
    public String getAsString(FacesContext context, UIComponent component, Object value) {
        if (!(value instanceof Modelo)) {
            return null;
        }

        return String.valueOf(((Modelo) value).getId());
    }
}

但是，下面的行会抛出一个NullPointerException，表示它modeloFacade是null。

Object o = modeloFacade.consultarPorId(Long.valueOf(value));

这是如何引起的，我该如何解决？

它抛出这个：

SEVERE: java.lang.NullPointerException
    at bean.AbstractFacade.consultarPorId(AbstractFacade.java:70)
    at converter.ModeloConverter.getAsObject(ModeloConverter.java:35)
    at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getConvertedValue(HtmlBasicInputRenderer.java:171)
    at com.sun.faces.renderkit.html_basic.MenuRenderer.convertSelectOneValue(MenuRenderer.java:202)
    at com.sun.faces.renderkit.html_basic.MenuRenderer.getConvertedValue(MenuRenderer.java:319)
    at org.primefaces.component.selectonemenu.SelectOneMenuRenderer.getConvertedValue(SelectOneMenuRenderer.java:55)
    at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1030)
    at javax.faces.component.UIInput.validate(UIInput.java:960)
    at javax.faces.component.UIInput.executeValidate(UIInput.java:1233)
    at javax.faces.component.UIInput.processValidators(UIInput.java:698)
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
    at org.primefaces.component.panel.Panel.processValidators(Panel.java:284)
    at javax.faces.component.UIForm.processValidators(UIForm.java:253)
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
    at javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:1172)
    at com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:76)
    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)

SEVERE:     at bean.AbstractFacade.consultarPorId(AbstractFacade.java:70)
SEVERE:     at converter.ModeloConverter.getAsObject(ModeloConverter.java:35)
SEVERE:     at com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getConvertedValue(HtmlBasicInputRenderer.java:171)
SEVERE:     at com.sun.faces.renderkit.html_basic.MenuRenderer.convertSelectOneValue(MenuRenderer.java:202)
SEVERE:     at com.sun.faces.renderkit.html_basic.MenuRenderer.getConvertedValue(MenuRenderer.java:319)
SEVERE:     at org.primefaces.component.selectonemenu.SelectOneMenuRenderer.getConvertedValue(SelectOneMenuRenderer.java:55)
SEVERE:     at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1030)
SEVERE:     at javax.faces.component.UIInput.validate(UIInput.java:960)
SEVERE:     at javax.faces.component.UIInput.executeValidate(UIInput.java:1233)
SEVERE:     at javax.faces.component.UIInput.processValidators(UIInput.java:698)
SEVERE:     at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
SEVERE:     at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
SEVERE:     at org.primefaces.component.panel.Panel.processValidators(Panel.java:284)
SEVERE:     at javax.faces.component.UIForm.processValidators(UIForm.java:253)
SEVERE:     at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
SEVERE:     at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
SEVERE:     at javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:1172)
SEVERE:     at com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:76)
SEVERE:     at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
SEVERE:     at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
SEVERE:     at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
SEVERE:     at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1550)
SEVERE:     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
SEVERE:     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
SEVERE:     at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
SEVERE:     at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
SEVERE:     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
SEVERE:     at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
SEVERE:     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
SEVERE:     at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
SEVERE:     at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
SEVERE:     at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
SEVERE:     at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:757)
SEVERE:     at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1056)
SEVERE:     at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:229)
SEVERE:     at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
SEVERE:     at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
SEVERE:     at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
SEVERE:     at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
SEVERE:     at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
SEVERE:     at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
SEVERE:     at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
SEVERE:     at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
SEVERE:     at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
SEVERE:     at java.lang.Thread.run(Thread.java:722)
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1 回答 1

0

嘿伙计们，我解决了我的问题。cosultarPorId 方法有问题。使用了错误的实体管理器。在这里，工作。

public Modelo consultarPorId(Long id) {
        CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();
        CriteriaQuery<Modelo> c = cb.createQuery(Modelo.class);        
        Root<Modelo> modelo = c.from(Modelo.class);        
        c.where(cb.equal(modelo.get("id"), cb.parameter(String.class, "id")));
        TypedQuery q = getEntityManager().createQuery(c);
        q.setParameter("id", id);    
        return (Modelo) q.getSingleResult();
    }

现在的问题是它没有保留在数据库上=/

于 2013-07-03T13:57:55.153 回答