NullPointerException przy używaniu EJB

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2015-10-24 13:01

Rejestracja: 7 lat temu

Ostatnio: 3 lata temu

0

Mam problem, gdy chcę użyć EJB (dopiero zaczynam). Używam WildFly 10, Intelij i Maven.

 import javax.ejb.Stateless;

@Stateless
public class SomethingBean implements Something {

//    @PersistenceContext(unitName = "myPU")
//    EntityManager entityManager;
//
//    public String getAuthor() {
//        return  entityManager.find(PostEntity.class, 1).getAuthor();
//    }

    @Override
    public String getSomething() {
        return "something";
    }

}

import javax.ejb.EJB;
import javax.faces.bean.RequestScoped;

@javax.faces.bean.ManagedBean
@RequestScoped
public class ManagedBean {

    @EJB
    private Something somethingBean;

    private String value;

    public ManagedBean() {
        this.value = somethingBean.getSomething();
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }
}
 <?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:h="http://xmlns.jcp.org/jsf/html"
      xmlns:ui="http://xmlns.jcp.org/jsf/facelets"
      xmlns:f="http://xmlns.jcp.org/jsf/core">

    <h:body>
        #{managedBean.value}
    </h:body>

</html> 

Pojawia się taki błąd:

Context Path:/unnamed
Servlet Path:/index.xhtml
Path Info:null
Query String:null
Stack Trace
javax.servlet.ServletException: Cant instantiate class: com.ManagedBean.
javax.faces.webapp.FacesServlet.service(FacesServlet.java:671)
io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:72)
io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
io.undertow.server.Connectors.executeRootHandler(Connectors.java:198)
io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:788)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
java.lang.Thread.run(Thread.java:745) 
12:44:00,065 SEVERE [javax.enterprise.resource.webcontainer.jsf.application] (default task-4) Error Rendering View[/index.xhtml]: javax.el.ELException: /index.xhtml: Cant instantiate class: com.ManagedBean.
    at com.sun.faces.facelets.compiler.TextInstruction.write(TextInstruction.java:90)
    at com.sun.faces.facelets.compiler.UIInstructions.encodeBegin(UIInstructions.java:82)
    at com.sun.faces.facelets.compiler.UILeaf.encodeAll(UILeaf.java:183)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:458)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:134)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:659)
    at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
    at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
    at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
    at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
    at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
    at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
    at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
    at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:72)
    at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
    at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
    at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
    at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
    at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
    at io.undertow.server.Connectors.executeRootHandler(Connectors.java:198)
    at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:788)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: com.sun.faces.mgbean.ManagedBeanCreationException: Cant instantiate class: com.ManagedBean.
    at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:191)
    at com.sun.faces.mgbean.BeanBuilder.build(BeanBuilder.java:100)
    at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:409)
    at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269)
    at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:257)
    at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:117)
    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.AstIdentifier.getValue(AstIdentifier.java:116)
    at com.sun.el.parser.AstValue.getBase(AstValue.java:150)
    at com.sun.el.parser.AstValue.getValue(AstValue.java:199)
    at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:226)
    at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:50)
    at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:50)
    at com.sun.faces.facelets.el.ELText$ELTextVariable.writeText(ELText.java:238)
    at com.sun.faces.facelets.el.ELText$ELTextComposite.writeText(ELText.java:154)
    at com.sun.faces.facelets.compiler.TextInstruction.write(TextInstruction.java:85)
    ... 39 more
Caused by: java.lang.NullPointerException
    at com.ManagedBean.<init>(ManagedBean.java:16)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
    at java.lang.Class.newInstance(Class.java:442)
    at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:186)
    ... 55 more

12:44:00,077 ERROR [io.undertow.request] (default task-4) UT005023: Exception handling request to /unnamed/index.xhtml: javax.servlet.ServletException: Cant instantiate class: com.ManagedBean.
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:671)
    at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
    at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
    at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
    at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
    at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
    at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
    at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
    at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:72)
    at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
    at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
    at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
    at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
    at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
    at io.undertow.server.Connectors.executeRootHandler(Connectors.java:198)
    at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:788)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: com.sun.faces.mgbean.ManagedBeanCreationException: Cant instantiate class: com.ManagedBean.
    at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:191)
    at com.sun.faces.mgbean.BeanBuilder.build(BeanBuilder.java:100)
    at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:409)
    at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269)
    at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:257)
    at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:117)
    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.AstIdentifier.getValue(AstIdentifier.java:116)
    at com.sun.el.parser.AstValue.getBase(AstValue.java:150)
    at com.sun.el.parser.AstValue.getValue(AstValue.java:199)
    at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:226)
    at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:50)
    at org.jboss.weld.el.WeldValueExpression.getValue(WeldValueExpression.java:50)
    at com.sun.faces.facelets.el.ELText$ELTextVariable.writeText(ELText.java:238)
    at com.sun.faces.facelets.el.ELText$ELTextComposite.writeText(ELText.java:154)
    at com.sun.faces.facelets.compiler.TextInstruction.write(TextInstruction.java:85)
    at com.sun.faces.facelets.compiler.UIInstructions.encodeBegin(UIInstructions.java:82)
    at com.sun.faces.facelets.compiler.UILeaf.encodeAll(UILeaf.java:183)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:458)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:134)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:659)
    ... 27 more
Caused by: java.lang.NullPointerException
    at com.ManagedBean.<init>(ManagedBean.java:16)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
    at java.lang.Class.newInstance(Class.java:442)
    at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:186)
    ... 55 more 

Ten sam problem, czyli NullPointerException, gdy próbuję użyć metody z beana występuje w każdym projekcie jaki tworzyłem (z użyciem JAX-RS i Glassfish albo Servletu). Co jest żle w tym kodzie? Przeglądałem już kilka tutoriali do EJB i wygląda na to, że we wstępie jest wszędzie mniej więcej taki sam jak mój. Co muszę zrobić, żeby używać EJB?

edytowany 1x, ostatnio: matis9988, 2015-10-24 13:21

Pozostało 580 znaków

2015-10-24 13:08
Moderator

Rejestracja: 12 lat temu

Ostatnio: 6 godzin temu

Lokalizacja: Wrocław

0

Tak na oko nigdzie nie tworzysz instancji klasy Something - ale mało znam się na Javie i EJB, więc z góry mea culpa, jeśli palnąłem jakąś bzdurę.


Pozostało 580 znaków

2015-10-24 14:44

Rejestracja: 6 lat temu

Ostatnio: 16 godzin temu

odwołanie somethingBean w konstruktorze nie zadziała użyj @PostConstrucotr

edytowany 1x, ostatnio: Szczery, 2015-10-24 14:44

Pozostało 580 znaków

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