@EJB注释bean的NullPointerException

时间：2013-03-05 21:30:58

标签： jsf converter

当我尝试覆盖getAsObject函数时出现问题

@FacesConverter("countryConverter")
public class CountryConverter implements Converter {

@EJB private CountryService countryService;

     @Override
        public Object getAsObject(FacesContext context, UIComponent arg1, String arg2){

         Country country = countryService.findByName(arg2);
         return country;
    }

}

当我在每个帖子中加载我的组合框时

<p:selectOneMenu value="#{registerController.selectedCountry}"
                converter="countryConverter">
                <f:selectItems value="#{registerController.countries}" var="country"
                    itemLabel="#{country.name}" itemValue="#{country}" />
            </p:selectOneMenu>

我在findbyName行中得到了一个nullPointer异常！我检查了arg2参数并且它有一个有效的值，我也测试了服务函数，并且它工作正常......在CountryConverter类之外。

我得到的错误是跟随，正如我在getAsObject函数行中描述的 

SEVERE: java.lang.NullPointerException
    at com.garagesalelive.controllers.converter.CountryConverter.getAsObject(CountryConverter.java:29)
    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:58)
    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 javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
    at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
    at org.primefaces.component.dialog.Dialog.processValidators(Dialog.java:378)
    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:1542)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
    at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
    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$AdapterCallable.call(ContainerMapper.java:317)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
    at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:849)
    at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:746)
    at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1045)
    at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:228)
    at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
    at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
    at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
    at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
    at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
    at com.sun.grizzly.util.AbstractThreadPool$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 com.garagesalelive.controllers.converter.CountryConverter.getAsObject(CountryConverter.java:29)
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:58)
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 javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
SEVERE:     at javax.faces.component.UIComponentBase.processValidators(UIComponentBase.java:1214)
SEVERE:     at org.primefaces.component.dialog.Dialog.processValidators(Dialog.java:378)
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:1542)
SEVERE:     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343)
SEVERE:     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
SEVERE:     at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
SEVERE:     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
SEVERE:     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
SEVERE:     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
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$AdapterCallable.call(ContainerMapper.java:317)
SEVERE:     at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
SEVERE:     at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:849)
SEVERE:     at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:746)
SEVERE:     at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1045)
SEVERE:     at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:228)
SEVERE:     at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
SEVERE:     at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
SEVERE:     at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
SEVERE:     at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
SEVERE:     at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
SEVERE:     at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
SEVERE:     at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
SEVERE:     at com.sun.grizzly.util.AbstractThreadPool$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)

3 个答案:

答案 0 :(得分：2)

我认为您的countryService为null。可能是注射问题。

试试这个

@ManagedBean
@RequestScoped
@FacesConverter("countryConverter")
public class CountryConverter implements Converter {...

答案 1 :(得分：1)

@EJB不适用于不受容器管理的bean。根据我的理解，它只适用于JSF Managed Beans，其他EJB和servlet。

如果您还使用CDI库，则可以尝试

@Inject private CountryService countryService;

或以其他方式进行查找，

    InitialContext ctx = new InitialContext();
    CountryService  countryService = 
(CountryService)ctx.lookup("ejb/countryService");

您的JNDI名称将取决于您的容器，或者如果您的容器支持并且由您在EJB上指定，则它将是EJB中mappedBy属性的值。

答案 2 :(得分：-2)

通过ManagedBean致电FacesContext：

 context.getApplication().getELResolver().getValue(context.getELContext(), null, "nameOfManagedBean");
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