Java websocket multiple client (TCP)

這篇主要解決的問題有兩個，一個在於同步 / 非同步下，多連接的處理方式。



同步型 TCP / multi client:
這樣的同步TCP應用的地方比較特殊，解決需要排隊才能交換資訊的方法。

若兩連接同時詢問，必須要等到伺服器一個個回應才可以。

Server 端:

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.logging.Level;
import java.util.logging.Logger;


/**
 *
 * @author MacTaylor.
 */
public class Server {

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

        ServerSocket welcomeSocket = new ServerSocket(1234);

        Responder h = new Responder();
        while (true) {
            // waiting..
            Socket connectionSocket = welcomeSocket.accept();
            Thread t = new Thread(new MyServer(h, connectionSocket));
            t.start();

        }
    }
}

class MyServer implements Runnable {

    Responder h;
    Socket connectionSocket;

    public MyServer(Responder h, Socket connectionSocket) {
        this.h = h;
        this.connectionSocket = connectionSocket;
    }

    @Override
    public void run() {

        while (h.responderMethod(connectionSocket)) {
            try {
                Thread.sleep(5000);
            } catch (InterruptedException ex) {
                ex.printStackTrace();
            }
        }

        try {
            connectionSocket.close();
        } catch (IOException ex) {
            Logger.getLogger(MyServer.class.getName()).log(Level.SEVERE, null, ex);
        }

    }

}

class Responder {
    String serverSentence;
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    synchronized public boolean responderMethod(Socket connectionSocket) {
        try {
            BufferedReader inFromClient= new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
            DataOutputStream outToClient= new DataOutputStream(connectionSocket.getOutputStream());
            String clientSentence = inFromClient.readLine();
            if (clientSentence == null || clientSentence.equals("EXIT")) {
                return false;
            }
            if (clientSentence != null) {
                System.out.println("client : " + clientSentence);
            }
            serverSentence = br.readLine() + "\n";
            outToClient.writeBytes(serverSentence);
            return true;
        } catch (SocketException e) {
            System.out.println("Disconnected");
            return false;
        }
    }
}

非同步型 TCP / multi client:
這樣的TCP適合作為典型的應用，也適合拿來做遊戲伺服器交換座標資訊。

Server 端:

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.util.logging.Level;
import java.util.logging.Logger;


/**
 *
 * @author MacTaylor.
 */
public class Server {

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

        ServerSocket welcomeSocket = new ServerSocket(1234);

        Responder h = new Responder();
        while (true) {
            // waiting..
            Socket connectionSocket = welcomeSocket.accept();
            Thread t = new Thread(new MyServer(h, connectionSocket));
            t.start();

        }
    }
}

class MyServer implements Runnable {

    Responder h;
    Socket connectionSocket;

    public MyServer(Responder h, Socket connectionSocket) {
        this.h = h;
        this.connectionSocket = connectionSocket;
    }

    @Override
    public void run() {

        while (h.responderMethod(connectionSocket)) {
            try {
                Thread.sleep(5000);
            } catch (InterruptedException ex) {
                ex.printStackTrace();
            }
        }

        try {
            connectionSocket.close();
        } catch (IOException ex) {
            Logger.getLogger(MyServer.class.getName()).log(Level.SEVERE, null, ex);
        }

    }

}

class Responder {
    String serverSentence;
    public boolean responderMethod(Socket connectionSocket) {
        try {
            BufferedReader inFromClient= new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
            DataOutputStream outToClient= new DataOutputStream(connectionSocket.getOutputStream());
            String clientSentence = inFromClient.readLine();
            if (clientSentence == null || clientSentence.equals("EXIT")) {
                return false;
            }
            if (clientSentence != null) {
                System.out.println("client : " + clientSentence);
            }
            serverSentence = "OK! i see "+ clientSentence +" \n";
            outToClient.writeBytes(serverSentence);
            return true;
        } catch (SocketException e) {
            System.out.println("Disconnected");
            return false;
        }
    }
}

至於 Client 實作是沒有分別的，但這只是一個測試用的連接，也可以同時使用其他語言的TCP做連接!


Client 端:

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.Socket;


/**
 *
 * @author MacTaylor.
 */
public class Client {

    public static void main(String argv[]) throws Exception {
        String sentence;
        String modifiedSentence;

        BufferedReader inFromUser
                = new BufferedReader(
                        new InputStreamReader(System.in));

        Socket clientSocket = new Socket("localhost", 6789);

        while (true) {
            DataOutputStream outToServer
                    = new DataOutputStream(
                            clientSocket.getOutputStream());

            BufferedReader inFromServer
                    = new BufferedReader(
                            new InputStreamReader(
                                    clientSocket.getInputStream()));
            sentence = inFromUser.readLine();
            outToServer.writeBytes(sentence + '\n');
            if (sentence.equals("EXIT")) {
                break;
            }
            modifiedSentence = inFromServer.readLine();
            System.out.println("FROM SERVER: " + modifiedSentence);

        }
        clientSocket.close();
    }
}

resource:
https://javadeveloperszone.wordpress.com/2013/04/20/java-tcp-chat-multiple-client/