向所有客户端发送消息(客户端 - 服务器通信)

Question

所以现在,我正在制作一个基于多线程的客户端服务器应用程序.在服务器端,我为接受的单独连接创建了一个线程.

在线程类中,我创建了一个向客户端发送命令的方法.我只想要的是,如何向所有正在运行的客户端发送参数？对于简单的声明,我只想让这个服务器向所有连接的客户端发送消息.

我已阅读此帖并sendToAll(String message)从此链接中找到方法.但是当我尝试使用我的代码时,没有类似的方法ServerSocket.

好的,这是我的服务器和线程的示例代码.

class ServerOne{

ServerSocket server = null;
...

ServerOne(int port){
            System.out.println("Starting server on port "+port);
    try{
      server = new ServerSocket(port);
              System.out.println("Server started successfully and now waiting for client");

    } catch (IOException e) {
      System.out.println("Could not listen on port "+port);
      System.exit(-1);
    }
}

public void listenSocket(){ 
    while(true){
        ClientWorker w;
        try{
            w = new ClientWorker(server.accept());
            Thread t = new Thread(w);
            t.start();
        } catch (IOException e) {
            System.out.println("Accept failed: 4444");
            System.exit(-1);
        }   
    }
}

protected void finalize(){
    try{
        server.close();
    } catch (IOException e) {
        System.out.println("Could not close socket");
        System.exit(-1);
    }
}
}

class ClientWorker implements Runnable{
Socket client;

ClientWorker(Socket client){
    this.client = client;
}
public void run(){
    ...
      sendCommand(parameter);
    ...
}

public void sendCommand(String command){
    PrintWriter out = null;
    try {
        out = new PrintWriter(client.getOutputStream(), true);
        out.println(command);
    } catch (IOException ex) {}
}

}

感谢帮助 :)

Answer 1

对于完整的服务器,建议不要使用以下答案,因此您应该将Java EE与servlet,Web服务等一起使用.

这仅适用于少数计算机要连接以执行特定任务的情况,并且使用简单的Java套接字不是一般问题.想想分布式计算或多人游戏.

编辑:我 - 从第一篇文章 - 大大更新了这个架构,现在测试和线程安全.任何需要它的人都可以在这里下载.

只需使用(直接或通过继承)Server和Client,start()他们,一切准备就绪.阅读内联注释以获得更强大的选项.

虽然客户之间的沟通相当复杂,但我会尽量简化它.

以下是服务器中的要点:

• 保留已连接客户端的列表.
• 为服务器输入定义一个线程.
• 定义接收消息的队列.
• 一个线程从队列中轮询,并使用它.
• 一些用于发送消息的实用方法.

对于客户:

• 为客户端输入定义一个线程.
• 定义接收消息的队列.
• 一个线程从队列中轮询,并使用它.

这是Server类:

public class Server {
    private ArrayList<ConnectionToClient> clientList;
    private LinkedBlockingQueue<Object> messages;
    private ServerSocket serverSocket;

    public Server(int port) {
        clientList = new ArrayList<ConnectionToClient>();
        messages = new LinkedBlockingQueue<Object>();
        serverSocket = new ServerSocket(port);

        Thread accept = new Thread() {
            public void run(){
                while(true){
                    try{
                        Socket s = serverSocket.accept();
                        clientList.add(new ConnectionToClient(s));
                    }
                    catch(IOException e){ e.printStackTrace(); }
                }
            }
        };

        accept.setDaemon(true);
        accept.start();

        Thread messageHandling = new Thread() {
            public void run(){
                while(true){
                    try{
                        Object message = messages.take();
                        // Do some handling here...
                        System.out.println("Message Received: " + message);
                    }
                    catch(InterruptedException e){ }
                }
            }
        };

        messageHandling.setDaemon(true);
        messageHandling.start();
    }

    private class ConnectionToClient {
        ObjectInputStream in;
        ObjectOutputStream out;
        Socket socket;

        ConnectionToClient(Socket socket) throws IOException {
            this.socket = socket;
            in = new ObjectInputStream(socket.getInputStream());
            out = new ObjectOutputStream(socket.getOutputStream());

            Thread read = new Thread(){
                public void run(){
                    while(true){
                        try{
                            Object obj = in.readObject();
                            messages.put(obj);
                        }
                        catch(IOException e){ e.printStackTrace(); }
                    }
                }
            };

            read.setDaemon(true); // terminate when main ends
            read.start();
        }

        public void write(Object obj) {
            try{
                out.writeObject(obj);
            }
            catch(IOException e){ e.printStackTrace(); }
        }
    }

    public void sendToOne(int index, Object message)throws IndexOutOfBoundsException {
        clientList.get(index).write(message);
    }

    public void sendToAll(Object message){
        for(ConnectionToClient client : clientList)
            client.write(message);
    }

}

这里是Client类:

public class Client {
    private ConnectionToServer server;
    private LinkedBlockingQueue<Object> messages;
    private Socket socket;

    public Client(String IPAddress, int port) throws IOException{
        socket = new Socket(IPAddress, port);
        messages = new LinkedBlokingQueue<Object>();
        server = new ConnecionToServer(socket);

        Thread messageHandling = new Thread() {
            public void run(){
                while(true){
                    try{
                        Object message = messages.take();
                        // Do some handling here...
                        System.out.println("Message Received: " + message);
                    }
                    catch(InterruptedException e){ }
                }
            }
        };

        messageHandling.setDaemon(true);
        messageHandling.start();
    }

    private class ConnectionToServer {
        ObjectInputStream in;
        ObjectOutputStream out;
        Socket socket;

        ConnectionToServer(Socket socket) throws IOException {
            this.socket = socket;
            in = new ObjectInputStream(socket.getInputStream());
            out = new ObjectOutputStream(socket.getOutputStream());

            Thread read = new Thread(){
                public void run(){
                    while(true){
                        try{
                            Object obj = in.readObject();
                            messages.put(obj);
                        }
                        catch(IOException e){ e.printStackTrace(); }
                    }
                }
            };

            read.setDaemon(true);
            read.start();
        }

        private void write(Object obj) {
            try{
                out.writeObject(obj);
            }
            catch(IOException e){ e.printStackTrace(); }
        }


    }

    public void send(Object obj) {
        server.write(obj);
    }
}