RMI初探

接口

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

public interface IFoo extends Remote {
    String say(String name) throws RemoteException;
}

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

public interface IBar extends Remote {
    String buy(String name) throws RemoteException;
}

实现

import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;

public class FooImpl /* extends UnicastRemoteObject */ implements IFoo {

    private int index;

    public FooImpl() throws RemoteException {
        this(0);
    }

    public FooImpl(int port) throws RemoteException {
        UnicastRemoteObject.exportObject(this, port);
    }

    @Override
    public String say(String name) throws RemoteException {
        String message = "say" + (index++);
        System.out.println(message);
        return name + ": " + message;
    }
}

import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;

public class BarImpl implements IBar {

    private int index;

    public BarImpl() throws RemoteException {
        this(0);
    }

    public BarImpl(int port) throws RemoteException {
        UnicastRemoteObject.exportObject(this, port);
    }

    @Override
    public String buy(String name) throws RemoteException {
        String message = "buy" + (index++);
        System.out.println(message);
        return name + ": " + message;
    }
}

Server

import java.net.MalformedURLException;
import java.rmi.AlreadyBoundException;
import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;

public class Server {

    public static void main(String[] args) throws RemoteException, AlreadyBoundException, MalformedURLException {

        IBar bar = new BarImpl();
        IFoo foo = new FooImpl();
        //方式一
        Registry registry = LocateRegistry.createRegistry(58082);
        registry.bind("bar", bar);
        //方式二
        Naming.bind("rmi://192.168.31.141:58082/foo", foo);

    }
}

bind 方法会向 RegistryImpl的Hashtable bindings属性put操作

服务端 registry 对象的属性如下

服务端有一个线程(RMI TCP Accept-58082) 监听 58082 端口

ObjectTable.objTable

ObjectTable.implTable

客户端

import java.rmi.Naming;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;

public class Client {

    public static void main(String[] args) throws Exception {

        //方式一
        Registry registry = LocateRegistry.getRegistry("192.168.31.141", 58082);
        IFoo foo = (IFoo) registry.lookup("foo");
        System.out.println(foo.say("druid"));

        //方式二
        IBar bar = (IBar) Naming.lookup("rmi://192.168.31.141:58082/bar");
        System.out.println(bar.buy("hikari"));
    }
}