如何在RMI方法的参数中传递对象？

Question

我正在尝试在RMI方法中添加参数。当我添加例如String一切正常。但是我不确定是否可以传递我创建的对象。我是RMI的新手，所以我的代码非常简单：

HelloIF

public interface HelloIF extends Remote {
    String greeting(Context c) throws RemoteException;
}

你好

public class Hello extends UnicastRemoteObject implements HelloIF {

    public Hello() throws RemoteException {
    }

    public String greeting(Context c) throws RemoteException {
        addToContext(c);
        report(c);
        return "greeting";
    }

    void addToContext(Context c) {
        c.addID(Thread.currentThread().getId());
    }

    void report(Context c) {
        System.out.println("Hello.greeting() thread : "
                + Thread.currentThread().getName() + " "
                + Thread.currentThread().getId());

        System.out.println("Hello.greeting() context : "
                + c.getDistributedThreadName() + " " + c.getRequestType());
    }
}

RMI服务器

public class RMIServer {

    public static void main(String[] args) throws RemoteException, MalformedURLException {
        LocateRegistry.createRegistry(1099);
        HelloIF hello = new Hello();
        Naming.rebind("server.Hello", hello);
        System.out.println("server.RMI Server is ready.");
        System.out.println("RMIServer.main() thread : " + Thread.currentThread().getName() 
                + " " + Thread.currentThread().getId());
    }
}

RMI客户端

public class RMIClient {
    public static void main(String[] args) throws RemoteException, MalformedURLException, NotBoundException {

        Context context = new Context("request1", Thread.currentThread().getName()+System.currentTimeMillis());

        Registry registry = LocateRegistry.getRegistry("localhost");
        HelloIF hello = (HelloIF) registry.lookup("server.Hello");
        System.out.println(hello.greeting(context));
        System.out.println("RMIClient.mian() thread : " + Thread.currentThread().getName() 
                + " " + Thread.currentThread().getId());
    }
}

最后是我的课堂上下文

public class Context 
{
    private String requestType;
    private String distributedThreadName;
    private List<Long> IDList;

   (...) getters/setters
}

我应该怎么做才能使传递上下文成为可能？

Answer 1

您的对象应实现Serializable。如我所见，这将是一个问题。之所以需要这样做是因为两个部分之间的通信是使用序列化完成的，因此需要发送给另一部分的每个对象都必须是实现类的实例Serializable。

public class Context implements Serializable
{
    private String requestType;
    private String distributedThreadName;
    private List<Long> IDList;

   (...) getters/setters
}

并请添加一个serialVersionUID作为一种很好的做法。就像是：

private static final long serialVersionUID = 20120731125400L;