CODEWITHSUNDEEP
javaclient
Dan
Dan

Reputation: 251

Client / Server model Java

I have a server class which connects a client on a specific server socket port and starts off a thread with a service class. Specifically, I have 3 service classes so I would like to have 3 different ports. This however, is not working as I had expected it to. This is my code for the server:

import java.net.ServerSocket;
import java.net.Socket;
import java.io.IOException;

public class WebsiteServer {

    public static void main(String args[]) throws IOException {

        ServerSocket serversocket = new ServerSocket(22401);
        ServerSocket serversocket2 = new ServerSocket(22402);
        Thread thread;
        Thread thread2;
        Socket socket;
        Socket socket2;
        NewUserService newuserservice;
        ExistingUserService existinguserservice;

        System.out.println("Waiting for clients to connect.");

        while (true) {

            socket = serversocket.accept();
            socket2 = serversocket2.accept();

            if(socket.isConnected()) {

                System.out.println("NewUserClient has connected.");
                newuserservice = new NewUserService(socket);
                thread = new Thread(newuserservice);
                thread.start();
            }

            if(socket2.isConnected()) {

                System.out.println("ExistingUserClient has connected.");
                existinguserservice = new ExistingUserService(socket2);
                thread2 = new Thread(existinguserservice);
                thread2.start();
            }
        }
    }
}

It works fine if I only use one port for example:

import java.net.ServerSocket;
import java.net.Socket;
import java.io.IOException;

public class WebsiteServer {

    public static void main(String args[]) throws IOException {

        ServerSocket serversocket = new ServerSocket(22401);
        ServerSocket serversocket2 = new ServerSocket(22402);
        Thread thread;
        Thread thread2;
        Socket socket;
        Socket socket2;
        NewUserService newuserservice;
        ExistingUserService existinguserservice;

        System.out.println("Waiting for clients to connect.");

        while (true) {

            socket = serversocket.accept();
            //socket2 = serversocket2.accept();

            if(socket.isConnected()) {

                System.out.println("NewUserClient has connected.");
                newuserservice = new NewUserService(socket);
                thread = new Thread(newuserservice);
                thread.start();
            }

//            if(socket2.isConnected()) {
//                
//                System.out.println("ExistingUserClient has connected.");
//                existinguserservice = new ExistingUserService(socket2);
//                thread2 = new Thread(existinguserservice);
//                thread2.start();
//            }
        }
    }
}

Any help would be appreciated.

Upvotes: 0

Views: 1540

Answers (3)

Ryan Amos
Ryan Amos

Reputation: 5452

You need to call the accept() method in a separate thread. accept() blocks the thread until someone joins the server. This could be 1 ms or 1 year.

I suggest you create an AcceptListener to be called when someone joins

public interface AcceptListener{
    public void socketAccepted(Socket s);
}

And a handler class

public class MyServerSocket extends Thread{
    private AcceptListener l;
    private boolean run = true;
    private ServerSocket s;
    public MyServerSocket(AcceptListener l, int port){
        this.l = l;
        this.s = new ServerSocket(port);
        this.start();
    }
    public void run(){
        while(run){
            l.socketAccepted(s.accept());
        }
    }
}

You'll have to handle errors and whatnot and make the overrides in you subclass(es) of AcceptListener.

Upvotes: 0

Sebastian
Sebastian

Reputation: 5873

accept()is a blocking method. In other words, the second accept() is waiting for another connection. Untik a second connection is accepted, your code will be blocked

Upvotes: 1

sethcall
sethcall

Reputation: 2907

The accept method blocks until a connection is made. So, you are sitting blocked one one .accept(), even though the other server may have activity. One simple solution would be to make one listening thread per server.

Upvotes: 1

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