Java RMI仅在本地主机上工作

Question

我正在处理一个瘦RMI客户端，但当我试图从除localhost之外的任何机器连接到它时，它会得到一个被拒绝的连接堆栈跟踪。我验证了我的防火墙已关闭。我还需要做什么。我需要为RMI配置安全性吗？

Server.java

package com.ibm.icm.autoconfig.server.rmi;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.ExportException;
import java.rmi.server.UnicastRemoteObject;
public final class Server extends Commands implements ServerHook {
    private Registry registry;
    public static void main(String[] args) throws RemoteException {
        Server server = new Server();
        server.Start();
    }
    private void Start() throws RemoteException {
        ServerHook serverHook = (ServerHook) UnicastRemoteObject.exportObject(this, 0);
        // Add serverHook to the local registry -- attempt to create registry
        // instance, if it fails to create, try finding an existing one
        try {
            registry = LocateRegistry.createRegistry(1099);
        } catch (ExportException ee) {
            registry = LocateRegistry.getRegistry(1099);
        }
        registry.rebind("ServerHook", serverHook);
        System.out.println("Server Running...");
        while (true) {
        }
    }
}

ServerHook.java

package com.ibm.icm.autoconfig.server.rmi;
import java.rmi.Remote;
import java.rmi.RemoteException;
public interface ServerHook extends Remote {
    public boolean write(String msg) throws RemoteException;
}

Client.java

package com.ibm.icm.autoconfig.client.rmi;
import java.rmi.NotBoundException;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import com.ibm.icm.autoconfig.server.rmi.ServerHook;
public class Client {
    private ServerHook serverHook;
    public static void main(String[] args) throws RemoteException, NotBoundException {
        Client client = new Client();
        client.connectTo("localhost");
        client.writeServer("Hello Server!");
    }
    private void connectTo(String serverHost) throws RemoteException, NotBoundException {
        Registry registry = LocateRegistry.getRegistry();
        serverHook = (ServerHook) registry.lookup("ServerHook");
    }
    private void writeServer(String msg) throws RemoteException {
        serverHook.write(msg);
    }
}

非本地RMI:的堆栈跟踪

Exception in thread "main" java.rmi.ConnectException: Connection refused to host: 9.65.186.135; nested exception is: 
    java.net.ConnectException: Connection refused: connect
    at sun.rmi.transport.tcp.TCPEndpoint.newSocket(Unknown Source)
    at sun.rmi.transport.tcp.TCPChannel.createConnection(Unknown Source)
    at sun.rmi.transport.tcp.TCPChannel.newConnection(Unknown Source)
    at sun.rmi.server.UnicastRef.newCall(Unknown Source)
    at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)
    at com.ibm.icm.autoconfig.client.rmi.Client.connectTo(Client.java:21)
    at com.ibm.icm.autoconfig.client.rmi.Client.main(Client.java:15)
Caused by: java.net.ConnectException: Connection refused: connect
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.PlainSocketImpl.doConnect(Unknown Source)
    at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.<init>(Unknown Source)
    at java.net.Socket.<init>(Unknown Source)
    at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(Unknown Source)
    at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(Unknown Source)
    ... 7 more

Answer 1

这是因为客户端有以下代码：

client.connectTo("localhost"); --> Client tries to connect to itself. Wrong

应将其更改为：

client.connectTo(serverHost);

其中serverHost是服务器代码运行的机器的地址

Answer 2

我在这里解决了这个问题。这与苏拉吉·钱德兰的建议类似。

private void connectTo(String serverHost) throws RemoteException, NotBoundException {
        Registry registry = LocateRegistry.getRegistry();
        serverHook = (ServerHook) registry.lookup("ServerHook");
}

条目LocateRegistry.getRegistry()本质上是让我的客户端指向它自己的注册表。正确的代码是：

private void connectTo(String **serverHost**) throws RemoteException, NotBoundException {
        Registry registry = LocateRegistry.getRegistry(**serverHost**);
        serverHook = (ServerHook) registry.lookup("ServerHook");
}