Java RMI 超时（崩溃）

发布于 2024-10-17 08:12:36 字数 956 浏览 4 评论 0原文

我正在使用 RMI 用 Java 编写服务器/客户端程序。当服务器崩溃时，这不是问题，客户端会收到 RemoteException 并断开连接。

但是，当客户端崩溃时我会遇到问题。我的服务器使用计时器时不时地对所有客户端对象执行 ping 操作，当它没有连接到客户端时，它将捕获 RemoteException。

然后，它应该从服务器中删除客户端对象（只需从列表中删除它），但这是不可能的，因为当我尝试对代理客户端对象执行任何操作时，它会抛出另一个 RemoteException。我该如何解决这个问题？

List<User> users;
Map<User, IClient> clients;

    class PingClients extends TimerTask {
          public void run() {
              for (IClient client : clients.values())
                try {
                    client.ping();
                } catch (RemoteException e) {
                    //removeClient(client); GENERATES REMOTEEXCEPTION
                }
          }

     }

     public boolean removeClient(IClient c) throws RemoteException{
          User u = c.getUser();
          users.remove(u);
          clients.remove(u);

          for (IClient client : clients.values())
              client.updateUsers(users);
      }

原文

I'm doing a server/client program in Java using RMI. When server crashes it's not a problem, clients get a RemoteException and disconnects.

However I have problems when clients crashes. My server uses a Timer to ping all client objects every now and then, when it gets no connection to a client it will catch a RemoteException.

Then, it's supposed to remove the client object from the server (just by removing it from a list), but it's impossible because when I try to do anything with the proxy client object it will throw another RemoteException. How can I solve this problem?

List<User> users;
Map<User, IClient> clients;

    class PingClients extends TimerTask {
          public void run() {
              for (IClient client : clients.values())
                try {
                    client.ping();
                } catch (RemoteException e) {
                    //removeClient(client); GENERATES REMOTEEXCEPTION
                }
          }

     }

     public boolean removeClient(IClient c) throws RemoteException{
          User u = c.getUser();
          users.remove(u);
          clients.remove(u);

          for (IClient client : clients.values())
              client.updateUsers(users);
      }

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

岁月染过的梦 2024-10-24 08:12:37

您会收到 RemoteException，因为当您尝试删除客户端（已断开连接）时，您首先调用客户端上的 getUser() 方法，这显然会引发 RemoteException。

您应该将代码更改为如下所示：

  class PingClients extends TimerTask {
      public void run() {
          for (Iterator<Map.Entry<User, IClient>> it = clients.entrySet().iterator(); it.hasNext(); )
            Entry<User, IClient> entry = it.next();
            try {
                IClient client = entry.getValue();
                client.ping();
            } 
            catch (RemoteException e) {
                it.remove();
            }
      }
  }

确保一次只有一个线程可以访问地图。

You get a RemoteException because when you try to remove the client (which is disconnected), you first call the getUser() method on the client, which obviously throws a RemoteException.

You should change your code to something like this :

  class PingClients extends TimerTask {
      public void run() {
          for (Iterator<Map.Entry<User, IClient>> it = clients.entrySet().iterator(); it.hasNext(); )
            Entry<User, IClient> entry = it.next();
            try {
                IClient client = entry.getValue();
                client.ping();
            } 
            catch (RemoteException e) {
                it.remove();
            }
      }
  }

Make sure that only one thread has access to the map at a time.

回复收藏 0 原文