java - 如何创建一个一次只接受一个连接的 rmi 服务器？

Question

我正在使用 rmi java 在 java 中编写客户端-服务器对。我希望服务器监听连接，当一个客户端连接时，服务器应拒绝任何其他尝试连接的客户端。

Answer 1

您需要使用 http://download.oracle.com/javase/6/docs/api/java/rmi/registry/LocateRegistry.html#createRegistry%28int,%20java.rmi.server.RMIClientSocketFactory,%20java.rmi.server.RMIServerSocketFactory%29 在代码中启动 RMI 注册表, 并写一个自定义 RMIServerSocketFactory返回仅接受单个连接的 ServerSocket。

编辑:与 LocateRegistry.createRegistry 的混搭和 http://download.oracle.com/javase/1.5.0/docs/guide/rmi/hello/Server.java添加了一些额外的代码(请注意，我没有编译它，因此您需要自己解决所有编译错误；它旨在向您展示一般用法):

编辑 2:修复它以纳入@EJP 的建议(有关详细信息，请参阅 this)。

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

public class Server implements Hello {

    public Server() {}

    public String sayHello() {
    return "Hello, world!";
    }

    public static void main(String args[]) {

    try {
        Server obj = new Server();
        RMIClientSocketFactory csf = new RMIClientSocketFactory() {
            @Override
            public Socket createSocket(String host, int port) throws IOException {
                InetAddress addr = InetAddress.getByName(host);
                if (addr.equals(InetAddress.getLocalHost())) {
                    return new Socket(addr, port);
                } else {
                    throw new IOException("remote socket bind forbidden.");
                }
            }
        };
        RMIServerSocketFactory ssf = new RMIServerSocketFactory() {
            @Override
            public ServerSocket createServerSocket(int port) throws IOException {
                System.out.println("RMIServerSocketFactory().createServerSocket()");
                return new ServerSocket(port, 1, InetAddress.getByName("127.0.0.1"));
            }
        };
        Hello stub = (Hello) UnicastRemoteObject.exportObject(obj, 0, csf, ssf);

        // Bind the remote object's stub in the registry
        Registry registry = LocateRegistry.createRegistry(uri.getPort(), csf, ssf);

        registry.bind("Hello", stub);

        System.err.println("Server ready");
    } catch (Exception e) {
        System.err.println("Server exception: " + e.toString());
        e.printStackTrace();
    }
    }
}