Question

我已经被困了两天，试图解决我的单例会话bean和独立（rmi）客户端之间的通信问题。这就是重点：我有一个远程会话bean（LoadBalancer），它可以被客户端（ChatRoom）访问，并且理论上也可以访问客户端。

远程接口：

public interface ILoadBalancer{

    public void addChatRoom( IChatRoom chatRoom );

    public void removeChatRoom( IChatRoom chatRoom );
}

会话bean：

@Remote(ILoadBalancer.class)
@Singleton
public class LoadBalancer implements ILoadBalancer {

/**
 * List of available chat rooms
 */
private Map<String, IChatRoom> chatRooms;


    private static final Logger logger = Logger.getLogger("loadBalancerLogger");

    @PostConstruct
    public void init() {
        chatRooms = new HashMap<String, IChatRoom>();
    }

    @Override
    public void addChatRoom(IChatRoom chatRoom) {
        // Adding a new chat room to the list of available chat rooms
        try {
            chatRooms.put(chatRoom.getName(), chatRoom);
            logger.log(Level.INFO, "Enregistrement d'un salon de discussion {0}", chatRoom.getName());
        } catch (RemoteException ex) {
            Logger.getLogger(LoadBalancer.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    @Override
    public void removeChatRoom(IChatRoom chatRoom) {
        // Removing a chat room from the list of available chat rooms
        try {
            chatRooms.remove(chatRoom.getName());
            logger.log(Level.INFO, "Suppression du salon de discussion {0}", chatRoom.getName());
        } catch (RemoteException ex) {
            Logger.getLogger(LoadBalancer.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

这些部署在glassfish服务器（4.1）中。

现在使用RMI的独立客户端：

public interface IChatRoom extends Remote {

    public int postMessage( String pseudo, String message) throws RemoteException;

    public int subscribe( String pseudo) throws RemoteException;

    public List<String> getNewMessages(String pseudo, int sequenceNumber) throws RemoteException;

    public String getName() throws RemoteException;
}

实施它的课程：

public class ChatRoom implements IChatRoom, Serializable {

    private String name;

    private List<String> users;

    private List<String> messages;

    private static final Logger logger = Logger.getLogger("chatRoomLogger");

    /**
     * A reference to the load balancer
     */
    private ILoadBalancer loadBalancer;

    public ChatRoom(String name) throws RemoteException, NamingException {
        this.name = name;
        users = new ArrayList<String>();
        messages = new ArrayList<String>();

        // Making the chat room available via RMI
        UnicastRemoteObject.exportObject(this);

        // Retrieving a reference to the loadBalancer
        Properties props = new Properties();
        props.setProperty(Context.INITIAL_CONTEXT_FACTORY, "com.sun.enterprise.naming.impl.SerialInitContextFactory");
        props.setProperty(Context.STATE_FACTORIES, "com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl");
        props.setProperty(Context.URL_PKG_PREFIXES, "com.sun.enterprise.naming");
        props.setProperty("org.omg.CORBA.ORBInitialHost", "localhost");
        props.setProperty("org.omg.CORBA.ORBInitialPort", "3700");

        Context ctx = new InitialContext(props);
        loadBalancer = (ILoadBalancer) ctx.lookup("java:global/loadBalancer/LoadBalancer!sn.esp.dgi.core.ILoadBalancer");

        loadBalancer.addChatRoom(this);
    }

    @Override
    public int postMessage(String pseudo, String message) throws RemoteException {
    // Not relevant to the problem
    }

    @Override
    public int subscribe(String pseudo) throws RemoteException {
        // Not relevant to the problem
    }

    @Override
    public List<String> getNewMessages(String pseudo, int sequenceNumber) throws RemoteException {
        // Not relevant to the problem
    }

    @Override
    public String getName() throws RemoteException {
        // Not Relevant to the problem
    }
}

如您所见，客户端具有对会话bean的远程引用，并且会话bean还具有对已订阅它的所有客户端的远程引用。

使用以下代码启动客户端：

public class ChatRoomLauncher {

    public static void main( String[] args ) {
        if( args.length < 1 ) {
            System.out.println("Usage: java ChatRoomLauncher <nomChatRoom>");
            System.exit(-1);
        }

        String chatRoomName = args[0];

        try {
            IChatRoom chatRoom = new ChatRoom(chatRoomName);
            System.out.println("Salon de discussion "+ chatRoomName +" démarré ");
        } catch (RemoteException ex) {
            Logger.getLogger(ChatRoomLauncher.class.getName()).log(Level.SEVERE, null, ex);
        } catch (NamingException ex) {
            Logger.getLogger(ChatRoomLauncher.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}

分别生成IChatRoom和ChatRoom的存根和骨架，并将IChatRoom的存根放在LoadBalancer部署的目录中后，我得到以下例外，这是我两天以来的噩梦：

Exception in thread "main" javax.ejb.NoSuchEJBException
    at sn.esp.dgi.core._ILoadBalancer_Wrapper.addChatRoom(sn/esp/dgi/core/_ILoadBalancer_Wrapper.java)
    at sn.esp.dgi.server.ChatRoom.<init>(ChatRoom.java:76)
    at sn.esp.dgi.server.ChatRoomLauncher.main(ChatRoomLauncher.java:29)
Caused by: java.rmi.NoSuchObjectException: CORBA INV_OBJREF 1330447539 No; nested exception is: 
    org.omg.CORBA.INV_OBJREF: WARNING: 00511203: Class sn.esp.dgi.server.ChatRoom not exported, or else is actually a JRMP stub  vmcid: OMG  minor code: 1203  completed: No
    at com.sun.corba.ee.impl.javax.rmi.CORBA.Util.mapSystemException(Util.java:260)
    at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.privateInvoke(StubInvocationHandlerImpl.java:211)
    at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.invoke(StubInvocationHandlerImpl.java:150)
    at com.sun.corba.ee.impl.presentation.rmi.codegen.CodegenStubBase.invoke(CodegenStubBase.java:226)
    at sn.esp.dgi.core.__ILoadBalancer_Remote_DynamicStub.addChatRoom(sn/esp/dgi/core/__ILoadBalancer_Remote_DynamicStub.java)
    ... 3 more
Caused by: org.omg.CORBA.INV_OBJREF: WARNING: 00511203: Class sn.esp.dgi.server.ChatRoom not exported, or else is actually a JRMP stub  vmcid: OMG  minor code: 1203  completed: No
    at com.sun.proxy.$Proxy54.objectNotExported(Unknown Source)
    at com.sun.corba.ee.impl.util.Utility.autoConnect(Utility.java:160)
    at com.sun.corba.ee.impl.javax.rmi.CORBA.Util.writeRemoteObject(Util.java:473)
    at com.sun.corba.ee.impl.presentation.rmi.DynamicMethodMarshallerImpl$12.write(DynamicMethodMarshallerImpl.java:356)
    at com.sun.corba.ee.impl.presentation.rmi.DynamicMethodMarshallerImpl.writeArguments(DynamicMethodMarshallerImpl.java:465)
    at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.privateInvoke(StubInvocationHandlerImpl.java:196)
    ... 6 more

异常告诉我，我没有导出chatRoom，虽然我已经生成并将其存根放在我认为应该存在的目录中。我试图通过PortableRemoteObject.exportObject（this）更改指令UnicastRemoteObject.exportObject（this），但我仍然遇到错误，与此不同。

非常感谢任何帮助。感谢

Answer 1

我遇到了完全相同的问题（在Glassfish 4服务器上运行的EJB，带有RMI回调对象的客户端），最后找到了解决方案！诀窍是：

使客户端实现继承自PortableRemoteObject，即在您的示例中：
```
public class ChatRoom extends PortableRemoteObject implements IChatRoom, Serializable
```
注意： Eclipse提供的PortableRemoteObject有3种选择： javax.rmi.PortableRemoteObject - ＆gt;不起作用，想要我没有为客户端对象生成的存根（错误消息：java.rmi.StubNotFoundException：找不到存根类） com.sun.corba.se.impl.javax.rmi.PortableRemoteObject - ＆gt;同样的问题 com.sun.corba.ee.impl.javax.rmi.PortableRemoteObject - ＆gt;工作，没有生成存根!!
在构造函数中导出对象（在您拥有UnicastRemoteObject.exportObject（this）的相同位置;）。从com.sun.corba.ee.impl.javax.rmi.PortableRemoteObject扩展类只允许使用：
```
exportObject(this); // i.e. non-static reference is required
```
注意：如果从javax.rmi.PortableRemoteObject扩展，则需要对PortableRemoteObject.exportObject（this）进行静态引用，但是我需要找到存根。你也可以尝试，因为你有存根。

希望这有帮助！

尝试从远程EJB访问远程客户端时出错

1 个答案: