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java - 为什么在 Wildfly 8.2.1 中访问 EJB 2.1 时出现 ClassCastException？

转载 作者：行者123 更新时间：2023-11-30 07:44:10 35 4
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我正在 Eclipse Luna 中使用 Java 1.7、XDoclet 1.2.3、W​​ildFly 8.2.1.Final、Dynamic Web Module 2.5、EJB 2.1。

  • 我有一个名为 P001_EAR 的企业应用程序项目。
  • 我有一个名为 P001_WAR 的动态 Web 项目。
  • 我有一个名为 P001_EJB 的 EJB 项目。
  • 我有一个名为 P001_EJBClient 的 EJB 客户端项目。

在P001_EJB中，我创建了一个XDoclet Stateless Session Bean (EJB 2.1)。

这是它的远程接口(interface):

package com.p001.ejb;

/**
 * Remote interface for Test1SLB.
 * @generated 
 * @wtp generated
 */
public interface Test1SLB extends javax.ejb.EJBObject
{
   /**
    * <!-- begin-xdoclet-definition -->
    * @generated //TODO: Must provide implementation for bean method stub    */
   public java.lang.String foo( java.lang.String param )
      throws java.rmi.RemoteException;    
}

这是它的主界面:

package com.p001.ejb;

/**
 * Home interface for Test1SLB.
 * @generated 
 * @wtp generated
 */
public interface Test1SLBHome extends javax.ejb.EJBHome
{
   public static final String COMP_NAME="java:comp/env/ejb/Test1SLB";
   public static final String JNDI_NAME="Test1SLB";

   public com.p001.ejb.Test1SLB create()
      throws javax.ejb.CreateException,java.rmi.RemoteException;
}

在P001_WAR中，我创建了一个名为P001Listener的Listener类；在其 contextInitialized 方法中，我尝试调用 Test1SLB EJB 的 foo 方法。这是它的代码:

public class P001Listener implements ServletContextListener {

    public P001Listener() {
    }

    public void contextInitialized(ServletContextEvent sce)  { 
         System.out.println("P001Listener.java: contextInitialized(ServletContextEvent sce): inside");
         String test1SLBJNDIName = null;
         Class test1SLBHomeClass = null;
         InitialContext initialContext = null;
         Object namedObject = null;
         Object ejbHomeObject = null;
         Test1SLBHome test1SLBHome = null;
         Test1SLB test1SLB = null;
         String rtnValue = null;


         try {

            test1SLBJNDIName = "java:global/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLB";
            System.out.println("P001Listener.java: contextInitialized(ServletContextEvent sce): test1SLBJNDIName=" + test1SLBJNDIName);

            test1SLBHomeClass = Test1SLBHome.class;
            System.out.println("P001Listener.java: contextInitialized(ServletContextEvent sce): test1SLBHomeClass=" + test1SLBHomeClass);

            initialContext = new InitialContext();
            System.out.println("P001Listener.java: contextInitialized(ServletContextEvent sce): initialContext=" + initialContext);

            namedObject = initialContext.lookup(test1SLBJNDIName);
            System.out.println("P001Listener.java: contextInitialized(ServletContextEvent sce): namedObject=" + namedObject);

            ejbHomeObject = PortableRemoteObject.narrow(namedObject, test1SLBHomeClass);
            System.out.println("P001Listener.java: contextInitialized(ServletContextEvent sce): ejbHomeObject=" + ejbHomeObject);

            test1SLBHome = (Test1SLBHome) ejbHomeObject;
            System.out.println("P001Listener.java: contextInitialized(ServletContextEvent sce): test1SLBHome=" + test1SLBHome);

            test1SLB = test1SLBHome.create();
            System.out.println("P001Listener.java: contextInitialized(ServletContextEvent sce): test1SLB=" + test1SLB);

            rtnValue = test1SLB.foo("pagal");
            System.out.println("P001Listener.java: contextInitialized(ServletContextEvent sce): rtnValue=" + rtnValue);

        } catch (NamingException ne) {
            ne.printStackTrace();

        } catch (ClassCastException cce) {
            cce.printStackTrace();

        } catch (RemoteException re) {
            re.printStackTrace();

        } catch (CreateException ce) {
            ce.printStackTrace();

        }
    }

    public void contextDestroyed(ServletContextEvent sce)  { 
        System.out.println("P001Listener.java: contextDestroyed(ServletContextEvent sce): inside");
    }

}

我在 WildFly 上部署了 P001_EAR。这是部署的样子:

P001_EAR.ear

在P001_EAR.ear里面我有:

  • 元信息
  • P001_EJB.jar
  • P001_WAR.war
  • P001_EJBClient.jar

在META-INF里面我有:

  • application.xml

在P001_EJB.jar里面我有:

  • META-INF\ejb-jar.xml
  • META-INF\jboss.xml
  • META-INF\MANIFEST.MF
  • com\p001\ejb\Test1SLBBean.class
  • com\p001\ejb\Test1SLBSession.class

在P001_WAR.war里面我有:

  • META-INF\MANIFEST.MF
  • WEB-INF\web.xml
  • WEB-INF\classes\com\p001\listener\P001Listener.class
  • WEB-INF\lib

在P001_EJBClient.jar里面我有:

  • META-INF\MANIFEST.MF
  • com\p001\ejb\Test1SLB.class
  • com\p001\ejb\Test1SLBHome.class
  • com\p001\ejb\Test1SLBLocal.class
  • com\p001\ejb\Test1SLBLocalHome.class
  • com\p001\ejb\Test1SLBUtil.class

我运行了 WildFly。在 server.log 文件中，我看到 EJB 已成功部署:

2015-12-08 11:21:58,671 INFO [org.jboss.as.ejb3.deployment.processors.EjbJndiBindingsDeploymentUnitProcessor] (MSC service thread 1-3) JNDI bindings for session bean named Test1SLB in deployment unit subdeployment "P001_EJB.jar" of deployment "P001_EAR.ear" are as follows:

java:global/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLBHome java:app/P001_EJB/Test1SLB!com.p001.ejb.Test1SLBHome java:module/Test1SLB!com.p001.ejb.Test1SLBHome java:jboss/exported/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLBHome java:global/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLBLocalHome java:app/P001_EJB/Test1SLB!com.p001.ejb.Test1SLBLocalHome java:module/Test1SLB!com.p001.ejb.Test1SLBLocalHome java:global/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLB java:app/P001_EJB/Test1SLB!com.p001.ejb.Test1SLB java:module/Test1SLB!com.p001.ejb.Test1SLB java:jboss/exported/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLB java:global/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLBLocal java:app/P001_EJB/Test1SLB!com.p001.ejb.Test1SLBLocal java:module/Test1SLB!com.p001.ejb.Test1SLBLocal

但是我在这一行得到java.lang.ClassCastException:

ejbHomeObject = PortableRemoteObject.narrow(namedObject, test1SLBHomeClass);

这是server.log:

2015-12-08 11:21:59,158 INFO [stdout] (MSC service thread 1-9) P001Listener.java: contextInitialized(ServletContextEvent sce): inside

2015-12-08 11:21:59,159 INFO [stdout] (MSC service thread 1-9) P001Listener.java: contextInitialized(ServletContextEvent sce): test1SLBJNDIName=java:global/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLB

2015-12-08 11:21:59,161 INFO [stdout] (MSC service thread 1-9) P001Listener.java: contextInitialized(ServletContextEvent sce): test1SLBHomeClass=interface com.p001.ejb.Test1SLBHome

2015-12-08 11:21:59,164 INFO [stdout] (MSC service thread 1-9) P001Listener.java: contextInitialized(ServletContextEvent sce): initialContext=javax.naming.InitialContext@2db02a6a

2015-12-08 11:21:59,171 INFO [org.jboss.ejb.client] (MSC service thread 1-9) JBoss EJB Client version 2.0.1.Final 2015-12-08 11:21:59,177 INFO [stdout] (MSC service thread 1-9) P001Listener.java: contextInitialized(ServletContextEvent sce): namedObject=Proxy for remote EJB StatelessEJBLocator{appName='P001_EAR', moduleName='P001_EJB', distinctName='', beanName='Test1SLB', view='interface com.p001.ejb.Test1SLB'}

2015-12-08 11:21:59,197 ERROR [stderr] (MSC service thread 1-9) java.lang.ClassCastException

2015-12-08 11:21:59,198 ERROR [stderr] (MSC service thread 1-9) at org.jboss.com.sun.corba.se.impl.javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:246)

2015-12-08 11:21:59,200 ERROR [stderr] (MSC service thread 1-9) at javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:158)

2015-12-08 11:21:59,201 ERROR [stderr] (MSC service thread 1-9) at com.p001.listener.P001Listener.contextInitialized(P001Listener.java:59)

2015-12-08 11:21:59,202 ERROR [stderr] (MSC service thread 1-9) at io.undertow.servlet.core.ApplicationListeners.contextInitialized(ApplicationListeners.java:173)

2015-12-08 11:21:59,204 ERROR [stderr] (MSC service thread 1-9) at io.undertow.servlet.core.DeploymentManagerImpl.deploy(DeploymentManagerImpl.java:194)

2015-12-08 11:21:59,206 ERROR [stderr] (MSC service thread 1-9) at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.startContext(UndertowDeploymentService.java:87)

2015-12-08 11:21:59,208 ERROR [stderr] (MSC service thread 1-9) at org.wildfly.extension.undertow.deployment.UndertowDeploymentService.start(UndertowDeploymentService.java:72)

2015-12-08 11:21:59,210 ERROR [stderr] (MSC service thread 1-9) at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1948)

2015-12-08 11:21:59,211 ERROR [stderr] (MSC service thread 1-9) at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1881)

2015-12-08 11:21:59,212 ERROR [stderr] (MSC service thread 1-9) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)

2015-12-08 11:21:59,214 ERROR [stderr] (MSC service thread 1-9) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

2015-12-08 11:21:59,215 ERROR [stderr] (MSC service thread 1-9) at java.lang.Thread.run(Thread.java:745)

2015-12-08 11:21:59,216 ERROR [stderr] (MSC service thread 1-9) Caused by: java.lang.ClassCastException: com.sun.proxy.$Proxy21 cannot be cast to org.omg.CORBA.Object

2015-12-08 11:21:59,218 ERROR [stderr] (MSC service thread 1-9) at org.jboss.com.sun.corba.se.impl.javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:225)

2015-12-08 11:21:59,219 ERROR [stderr] (MSC service thread 1-9) ... 11 more

我做错了什么才会收到此错误消息？

谢谢

更新

我已经找到解决办法了。当我更改此代码时:

test1SLBJNDIName = "java:global/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLB";

这段代码:

test1SLBJNDIName = "java:global/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLBHome";

然后就成功了。所以基本上我现在正在查找 JNDI Home 名称，然后将其转换为 Home Class。

在旧的 JBoss 4.2.X 中，我查找 JNDI 名称 Test1SLB ，然后将其转换为 Home Class 并且它起作用了。那么在旧的 JBoss 4.2.X 中是否有 1 个 JNDI 名称 Test1SLB 用于远程和主目录？

最佳答案

我已经找到解决办法了。当我更改此代码时:

test1SLBJNDIName = "java:global/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLB";

这段代码:

test1SLBJNDIName = "java:global/P001_EAR/P001_EJB/Test1SLB!com.p001.ejb.Test1SLBHome";

然后就成功了。所以基本上我现在正在查找 Home，然后将其转换到 Home Class。

在旧的 JBoss 4.2.X 中，我查找 JNDI 名称 Test1SLB ，然后将其转换为 Home Class 并且它起作用了。因此，在旧的 JBoss 4.2.X 中，有 1 个 JNDI 名称 Test1SLB 用于远程和主目录。

关于java - 为什么在 Wildfly 8.2.1 中访问 EJB 2.1 时出现 ClassCastException？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34162487/

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