NullPointerException異常的@EJB註釋豆

我有一個問題，當我嘗試重寫的getAsObject功能NullPointerException異常的@EJB註釋豆

@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; 
    } 

}

所以，當我打開我的組合框在每一個崗位回到

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

我得到了一個空指針異常findbyName行！，我檢查arg2參數，並且它擁有一個有效的值，並且我測試了服務函數，並且它工作正常...在CountryConverter類之外。

，我得到的錯誤是後續，我在的getAsObject功能線

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)

來源

2013-03-05 David Agustin Almanza Gaitan

添加二傳手對'CountryService countryService'屬性，否則就不能注射。 – 2013-03-05 22:21:58

我不認爲setter方法是EJB註釋所必需的。那種EJB是什麼？如果它是本地的並且在同一個應用程序中運行，那麼它應該可以工作。可以使用您正在使用的註釋發佈您的EJB。 – 2013-03-06 00:34:52

本地公共接口CountryService延伸DAO {} 無國籍公共類CountryServiceImpl實現CountryService {} 公共接口CountryDao延伸DAO {} 無國籍公共類CountryDaoImpl實現CountryDao {} ===== === 注意「@」符號被假設是每個EJB保留字之前，但堆棧不允許我的[JSF2 cuze他提到用戶語法 – 2013-03-06 15:35:01

@EJB不會在沒有容器管理豆的工作。根據我的理解，它僅適用於JSF Managed Beans，其他EJB和servlet。

如果您還使用CDI庫，那麼你可以試試，

@Inject private CountryService countryService;

或以其他方式進行查找，

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

您的JNDI名稱將取決於您的容器上或將成爲的mappedBy的值屬性，如果你的容器支持這個屬性，並且你是在EJB上指定的。

來源

2013-03-06 03:49:29

EJB注入在我的ManagedBean中正常工作，我在我的@PostConstruct中測試，它解決了正確的實現，但是當我嘗試在Converter Implementation類上使用它時，它失敗並且看起來是空的！所以第一種方法適用於我！ – 2013-03-06 15:55:45

我沒有注意到你在轉換器中使用它，我編輯了我的回答 – 2013-03-06 16:33:19

這是正確的男人，我使用初始上下文來提供服務國家和它工作正常！非常感謝 – 2013-03-06 17:50:20

描述，我認爲你的countryService爲空。可能是注射問題。

試試這個

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

來源

2013-03-05 21:37:24

使轉換器成爲一個託管bean不會解決問題。另外，最好將其設置爲'@ ApplicationScoped'，以便只爲所有應用程序使用一次，而不是爲每個請求創建一個轉換器。 – 2013-03-05 22:23:17

@LuiggiMendoza，其實它會的。根據JSF 2.0規範，只有作用域bean纔是符合注入條件的目標。轉換器不是，這就是OP注入失敗的原因。我自己已經成功地使用（並推薦）了這個技巧。即使你在這裏搜索，我相信你會在這裏找到答案。你在'@ RequestScoped'位上是正確的。這是不必要的，'@ ManagedBean'就足以達到預期的目的。 Kerem Can Kurtay也應該擺脫轉換器命名，並將名稱放在託管bean註釋上。正是這個名字將在標記 – kolossus 2013-03-06 04:23:03

@kolossus中使用，那麼託管bean將是'@ NoneScoped'，因此每次在JSF代碼中調用'countryConverter'時都會創建bean。感謝您的教訓，但我仍然認爲它應該是'@ ApplicationScoped'，以便擁有一個實例並且不會爲GC提供額外的工作。 – 2013-03-06 04:34:15

-2

通過調用ManagedBean通過FacesContext：

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

來源

2013-11-02 13:44:37 user2947843

NullPointerException異常的@EJB註釋豆

回答

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