错误 javax.naming.NamingException

Question

我是使用 j2ee 的新手，当我使用 netbean 6.9 运行这个项目时。我遇到了这个问题

javax.naming.NamingException: Lookup failed for 'java:comp/env' in SerialContext  [Root exception is javax.naming.NamingException: Invocation exception: Got null ComponentInvocation ]
        at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:442)
        at javax.naming.InitialContext.lookup(InitialContext.java:392)
        at javax.naming.InitialContext.lookup(InitialContext.java:392)
        at com.askad.ap.util.ListReader.readPath(ListReader.java:34)
        at com.askad.ap.util.ListReader.<init>(ListReader.java:29)
        at com.askad.ap.facade.UserTransactionFacade.<init>(UserTransactionFacade.java:44)
        at com.askad.ap.facade.__EJB31_Generated__UserTransactionFacade__Intf____Bean__.<init>(Unknown Source)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        at java.lang.Class.newInstance0(Class.java:355)
        at java.lang.Class.newInstance(Class.java:308)
        at com.sun.ejb.containers.BaseContainer.instantiateOptionalEJBLocalBusinessObjectImpl(BaseContainer.java:3801)
        at com.sun.ejb.containers.StatelessSessionContainer.initializeHome(StatelessSessionContainer.java:248)
        at com.sun.ejb.containers.ContainerFactoryImpl.createContainer(ContainerFactoryImpl.java:161)
        at org.glassfish.ejb.startup.EjbApplication.loadContainers(EjbApplication.java:207)
        at org.glassfish.ejb.startup.EjbDeployer.load(EjbDeployer.java:197)
        at org.glassfish.ejb.startup.EjbDeployer.load(EjbDeployer.java:63)
        at org.glassfish.internal.data.ModuleInfo.load(ModuleInfo.java:175)
        at org.glassfish.internal.data.ApplicationInfo.load(ApplicationInfo.java:216)
        at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:338)
        at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:183)
        at org.glassfish.deployment.admin.DeployCommand.execute(DeployCommand.java:272)
        at com.sun.enterprise.v3.admin.CommandRunnerImpl$1.execute(CommandRunnerImpl.java:305)
        at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:320)
        at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:1176)
        at com.sun.enterprise.v3.admin.CommandRunnerImpl.access$900(CommandRunnerImpl.java:83)
        at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1235)
        at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1224)
        at com.sun.enterprise.v3.admin.AdminAdapter.doCommand(AdminAdapter.java:365)
        at com.sun.enterprise.v3.admin.AdminAdapter.service(AdminAdapter.java:204)
        at com.sun.grizzly.tcp.http11.GrizzlyAdapter.service(GrizzlyAdapter.java:166)
        at com.sun.enterprise.v3.server.HK2Dispatcher.dispath(HK2Dispatcher.java:100)
        at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:245)
        at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
        at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
        at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
        at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
        at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
        at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
        at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
        at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
        at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
        at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
        at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
        at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
        at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
        at java.lang.Thread.run(Thread.java:662)
Caused by: javax.naming.NamingException: Invocation exception: Got null ComponentInvocation 
        at com.sun.enterprise.naming.impl.GlassfishNamingManagerImpl.getComponentId(GlassfishNamingManagerImpl.java:773)
        at com.sun.enterprise.naming.impl.GlassfishNamingManagerImpl.lookup(GlassfishNamingManagerImpl.java:655)
        at com.sun.enterprise.naming.impl.JavaURLContext.lookup(JavaURLContext.java:156)
        at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:428)
        ... 48 more

当我点击时

com.askad.ap.util.ListReader.readPath(ListReader.java:34)

NetBean 突出显示这一行

Context env = (Context) new InitialContext().lookup("java:comp/env");

有人知道如何解决这个问题吗？这个问题是什么原因造成的？谢谢b4

Answer 1

从堆栈跟踪来看，您似乎正在使用 Glassfish 作为容器。在 context.xml 中，您应该定义一个或多个资源。假设您有一个名为 jdbc/msql。然后你会使用 java:comp/env/jdbc/msql 来引用它。看起来您指的是那行有问题的代码中的一些空资源。嗯。

Answer 2

我在尝试从无法访问的线程访问 java:comp/env 命名空间时看到了该异常。我通过使用全局标识符来解决它（例如，只是“jdbc/msql”而不是“java:comp/env/jdbc/msql”）。

您也可以在可能的地方获取对象一次（例如，通过@Resource 注入），然后从任何线程引用它。

Answer 3

如果您在 glassfish 中遇到此错误，请尝试查找文件 sun-web.xml。 如果此文件丢失，可能会发生这种情况。