Java EE 6 Java消息传递服务不可追踪的NullPointerException

我正在尝试在我的GlassFish项目中设置JMS

我遵循《JavaEE6与GlassFish3应用服务器》一书中的指导原则

我将连接器资源设置为“jms/GlassFishWebDevConnectionFactory”，将队列设置为“jms/GlassFishWebDevQueue”

以下代码在单例Bean中执行：

public class MessageSender {
    @Resource(mappedName = "jms/GlassFishWebDevConnectionFactory")
    private ConnectionFactory connectionFactory;
    @Resource(mappedName = "jms/GlassFishWebDevQueue")
    private Queue queue;
    public void postMessages() {
        try {
            Connection con = connectionFactory.createConnection();
        }catch (JMSException ex) {
           Logger.getLogger(MessageSender.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}

应用程序的初始化在带有NullPointerException的“Connection con=connectionFactory.createConnection（）；”处失败

这是完整的堆栈跟踪：

javax.ejb.CreateException: Initialization failed for Singleton WorldBean
    at com.sun.ejb.containers.AbstractSingletonContainer.createSingletonEJB(AbstractSingletonContainer.java:547)
    at com.sun.ejb.containers.AbstractSingletonContainer.access$100(AbstractSingletonContainer.java:79)
    at com.sun.ejb.containers.AbstractSingletonContainer$SingletonContextFactory.create(AbstractSingletonContainer.java:719)
    at com.sun.ejb.containers.AbstractSingletonContainer.instantiateSingletonInstance(AbstractSingletonContainer.java:451)
    at org.glassfish.ejb.startup.SingletonLifeCycleManager.initializeSingleton(SingletonLifeCycleManager.java:216)
    at org.glassfish.ejb.startup.SingletonLifeCycleManager.initializeSingleton(SingletonLifeCycleManager.java:210)
    at org.glassfish.ejb.startup.SingletonLifeCycleManager.initializeSingleton(SingletonLifeCycleManager.java:177)
    at org.glassfish.ejb.startup.SingletonLifeCycleManager.doStartup(SingletonLifeCycleManager.java:155)
    at org.glassfish.ejb.startup.EjbApplication.start(EjbApplication.java:177)
    at org.glassfish.internal.data.EngineRef.start(EngineRef.java:130)
    at org.glassfish.internal.data.ModuleInfo.start(ModuleInfo.java:269)
    at org.glassfish.internal.data.ApplicationInfo.start(ApplicationInfo.java:301)
    at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:461)
    at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:240)
    at org.glassfish.deployment.admin.DeployCommand.execute(DeployCommand.java:389)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl$1.execute(CommandRunnerImpl.java:348)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:363)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:1085)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl.access$1200(CommandRunnerImpl.java:95)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1291)
    at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1259)
    at com.sun.enterprise.v3.admin.AdminAdapter.doCommand(AdminAdapter.java:461)
    at com.sun.enterprise.v3.admin.AdminAdapter.service(AdminAdapter.java:212)
    at com.sun.grizzly.tcp.http11.GrizzlyAdapter.service(GrizzlyAdapter.java:179)
    at com.sun.enterprise.v3.server.HK2Dispatcher.dispath(HK2Dispatcher.java:117)
    at com.sun.enterprise.v3.services.impl.ContainerMapper$Hk2DispatcherCallable.call(ContainerMapper.java:354)
    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:636)
Caused by: java.lang.NullPointerException
    at tier_controller.MessageSender.postMessages(MessageSender.java:31)
    at tier_controller.WorldBean.init(WorldBean.java:28)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at com.sun.ejb.containers.interceptors.BeanCallbackInterceptor.intercept(InterceptorManager.java:1009)
    at com.sun.ejb.containers.interceptors.CallbackChainImpl.invokeNext(CallbackChainImpl.java:65)
    at com.sun.ejb.containers.interceptors.CallbackInvocationContext.proceed(CallbackInvocationContext.java:113)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doCallback(SystemInterceptorProxy.java:138)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.init(SystemInterceptorProxy.java:120)
    at sun.reflect.GeneratedMethodAccessor106.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at com.sun.ejb.containers.interceptors.CallbackInterceptor.intercept(InterceptorManager.java:964)
    at com.sun.ejb.containers.interceptors.CallbackChainImpl.invokeNext(CallbackChainImpl.java:65)
    at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:393)
    at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:376)
    at com.sun.ejb.containers.AbstractSingletonContainer.createSingletonEJB(AbstractSingletonContainer.java:538)
    ... 40 more<code>

我已经花了好几个小时来处理这个问题，我查了两次我找到的每一个tipp。所需的资源正在运行，@Resource语法也应该有效

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我完全不知道该如何跟踪或修复此错误

如果您想调试它以找出问题所在-您可以在jpda选项中设置挂起标志，以便在应用程序开始初始化之前连接到调试。

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另外，如果需要，您可以在IDE中为NPE设置断点异常（在Intellij Idea中，运行->查看断点->..）。

您的connectionFactory为空，它不是由容器初始化的。我从那里开始…嗯，是的，当然是空的。。。问题是为什么。名称空间是正确的，ressource是连接的，我遵循了书中的每一步。我在研究过程中遇到了很多类似的问题，但没有一个回答可以解释为什么它可能是空的。你的代码是正确的。解释如何在GlassFish管理控制台中设置JMS和ConnectionFactory我最终解决了这个问题。问题是，servlet没有loadOnStartup=1注释。我仍然不相信，为什么这实际上是一个问题，但它解决了这个问题。