Question

我有以下JSF2控制器/ bb，我注入了一个会话bean。但是，它无法获得对EJB本地会话Bean的引用。

JSF2 Backing Bean：

@ManagedBean
@Named("scorecardBackingBean")
@SessionScoped
public class ScorecardBackingBean implements Serializable {
    private static final long serialVersionUID = 7231502115861150753L;

    @Inject
    private IScorecardServiceBean scorecardServiceBean;

    @PostConstruct
    private void prepareMainLineChart() {
        this.mainLineChart = new CartesianChartModel();


         List<OrderVolume> orderVolumeList = this.scorecardServiceBean
         .getOrderVolume(); //ERROR here, scorecardServiceBean is null.
}

EJB：

@Stateless
public class ScorecardServiceBean implements IScorecardServiceBean {
}

EJB接口：

@Local
public interface IScorecardServiceBean {
    List<OrderVolume> getOrderVolume();
}

遇到错误：

java.lang.IllegalStateException: JBAS011048: Failed to construct component instance
    at org.jboss.as.ee.component.BasicComponent.constructComponentInstance(BasicComponent.java:163)
    at org.jboss.as.ee.component.BasicComponent.createInstance(BasicComponent.java:95)
    at org.jboss.as.web.deployment.component.WebComponentInstantiator$2.<init>(WebComponentInstantiator.java:96)
    at org.jboss.as.web.deployment.component.WebComponentInstantiator.initializeInstance(WebComponentInstantiator.java:94)
.................
Caused by: java.lang.NullPointerException
    at sg.java.bus.controller.scorecard.ScorecardBackingBean.prepareMainLineChart(ScorecardBackingBean.java:79)
    at sg.java.bus.controller.scorecard.ScorecardBackingBean.init(ScorecardBackingBean.java:61)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.jboss.as.ee.component.ManagedReferenceLifecycleMethodInterceptorFactory$ManagedReferenceLifecycleMethodInterceptor.processInvocation(ManagedReferenceLifecycleMethodInterceptorFactory.java:130)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
    at org.jboss.invocation.WeavedInterceptor.processInvocation(WeavedInterceptor.java:53)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
    at org.jboss.as.ee.component.ManagedReferenceInterceptorFactory$ManagedReferenceInterceptor.processInvocation(ManagedReferenceInterceptorFactory.java:106)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
    at org.jboss.invocation.WeavedInterceptor.processInvocation(WeavedInterceptor.java:53)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
    at org.jboss.as.ee.component.TCCLInterceptor.processInvocation(TCCLInterceptor.java:45)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288)
    at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
    at org.jboss.as.ee.component.BasicComponent.constructComponentInstance(BasicComponent.java:161)
    ... 52 more

Answer 1

您正在混合使用CDI托管bean（@Named）和JSF托管bean（@ManagedBean）。这些注释中只有一个是必要的。

如果您选择其中一个，请确保导入正确的范围类。

CDI：javax.enterprise.context.SessionScoped

JSF：javax.faces.bean.SessionScoped

查看这些相关问题＆amp;背景信息的答案：

JSF2 Backing Bean无法获得对@Inject'ed Session Bean的引用

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