java - Raspberry Pi 上的 RMI 不起作用连接拒绝主机 : 127. 0.0.1

Question

我正在尝试使用 java RMI 在服务器(在 Pi 上)和客户端(在另一个 PI 上)之间进行通信。客户端能够调用服务器的远程方法，但是当服务器尝试访问客户端的远程方法时，我收到错误 连接拒绝主机 127.0.0.1。 为了解决这个问题，我设置了 System.setProperty("java.rmi.server.hostname", ServerIP; 但随后出现 Connectionrejected to Host 10.10.*.*.

的错误

MasterInterface 看起来像

import java.rmi.Remote;
import java.rmi.RemoteException;


public interface MasterInterface extends Remote{
    public void sayHello(String s) throws RemoteException;

}

Master.java 文件看起来像

import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.UnicastRemoteObject;


public class Master extends UnicastRemoteObject implements MasterInterface{

    protected Master() throws RemoteException {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        try {
        System.setProperty("java.rmi.server.hostname", "192.168.4.*");
            Master master = new Master();
            Registry reg = LocateRegistry.createRegistry(9898);
            reg.rebind("Master", master);
            System.out.println("Master is on.123123132.test.");


        } catch (RemoteException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


    }

    @Override
    public void sayHello(String s) throws RemoteException {
        // TODO Auto-generated method stub
        System.out.println("Hiiiiiii ->>>>>"+s);
        try{

        Registry regi2 = LocateRegistry.getRegistry("192.168.*.*", 9898);
        System.out.println("asdasdasd1!!");
        SlaveInterface bsObj1 = (SlaveInterface) regi2.lookup("Slave");
        bsObj1.saybye("madhav");
        }catch(Exception e){
            e.printStackTrace();
        }

    }

}

SlaveInterface 看起来像

    import java.rmi.Remote;
    import java.rmi.RemoteException;


    public interface SlaveInterface extends Remote{

        public void saybye(String s) throws RemoteException;

    }

Slave.java 文件看起来像

import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.UnicastRemoteObject;


public class Slave extends UnicastRemoteObject implements SlaveInterface {
    private final static String master_IP = "192.168.4.*";
    protected Slave() throws RemoteException {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        try{
            System.setProperty("java.rmi.server.hostname", "192.168.*.*");
            Slave s = new Slave();
        Registry regclient = LocateRegistry.createRegistry(2525);
        System.out.println("slave obj bound!!");
        regclient.rebind("Slave", s);
        System.out.println("Slave is on..");

        Registry regi = LocateRegistry.getRegistry(master_IP, 9898);
        System.out.println("slave obj bound1111!!");
        MasterInterface bsObj = (MasterInterface) regi.lookup("Master");
        System.out.println("slave obj bound2222!!");
        bsObj.sayHello("hi karan");
        System.out.println("done................");
        }catch(Exception e){
            System.out.println("not working!!!!!!!!!!");
            e.printStackTrace();
        }

    }

    @Override
    public void saybye(String s) throws RemoteException {
        // TODO Auto-generated method stub
        System.out.println("bye "+s);


    }

}

Answer 1

在导出任何远程对象之前，将 java.rmi.server.hostname 设置为服务器 JVM 中服务器的外部 IP 地址。请参阅RMI FAQ item A.1 .