Java Socket Example

Trail: Custom Networking

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class Server {

    public static void main(String[] args) {
        new Server().startServer();
    }

    public void startServer() {
        final ExecutorService clientProcessingPool = Executors.newFixedThreadPool(10);

        Runnable serverTask = new Runnable() {
            public void run() {
                try {
                    ServerSocket serverSocket = new ServerSocket(9999);
                    System.out.println("Waiting for clients to connect...");
                    while (true) {
                        Socket clientSocket = serverSocket.accept();
                        clientProcessingPool.submit(new ClientTask(clientSocket));
                    }
                } catch (Exception e) {
                    System.err.println("Unable to process client request");
                    e.printStackTrace();
                }
            }
        };
        Thread serverThread = new Thread(serverTask);
        serverThread.start();

    }

    private class ClientTask implements Runnable {
        private final Socket clientSocket;

        private ClientTask(Socket clientSocket) {
            this.clientSocket = clientSocket;
        }

        public void run() {
            System.out.println("Got a client !");
            // Do whatever required to process the client's request
            try {
                System.out.println("Just connected to " + clientSocket.getRemoteSocketAddress());
                OutputStream outToServer = clientSocket.getOutputStream();
                DataOutputStream out = new DataOutputStream(outToServer);

                out.writeUTF("Hello from " + clientSocket.getLocalSocketAddress());

                InputStream inFromServer = clientSocket.getInputStream();
                DataInputStream in = new DataInputStream(inFromServer);
                System.out.println("Server says " + in.readUTF());
                clientSocket.close();

                try {
                    clientSocket.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketTimeoutException;

public class GreetingServer extends Thread {
    private ServerSocket serverSocket;

    public GreetingServer(int port) throws IOException {
        serverSocket = new ServerSocket(port);
        serverSocket.setSoTimeout(1000000);
    }

    public void run() {
        while (true) {
            try {
                System.out.println("Waiting for client on port " +
                        serverSocket.getLocalPort() + "...");
                Socket server = serverSocket.accept();
                System.out.println("Just connected to "
                        + server.getRemoteSocketAddress());

                DataInputStream in =
                        new DataInputStream(server.getInputStream());
                System.out.println(in.readUTF());
                DataOutputStream out =
                        new DataOutputStream(server.getOutputStream());
                out.writeUTF("Thank you for connecting to "
                        + server.getLocalSocketAddress() + "\nGoodbye!");
                server.close();
            } catch (SocketTimeoutException s) {
                System.out.println("Socket timed out!");
                break;
            } catch (IOException e) {
                e.printStackTrace();
                break;
            }
        }
    }

    public static void main(String[] args) {
        int port = Integer.parseInt(args[0]);
        try {
            Thread t = new GreetingServer(port);
            t.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

public class GreetingClient {
    public static void main(String[] args) {
        String serverName = args[0];
        int port = Integer.parseInt(args[1]);
        try {
            System.out.println("Connecting to " + serverName
                    + " on port " + port);
            Socket client = new Socket(serverName, port);
            System.out.println("Just connected to "
                    + client.getRemoteSocketAddress());
            OutputStream outToServer = client.getOutputStream();
            DataOutputStream out =
                    new DataOutputStream(outToServer);

            out.writeUTF("Hello from "
                    + client.getLocalSocketAddress());
            InputStream inFromServer = client.getInputStream();
            DataInputStream in =
                    new DataInputStream(inFromServer);
            System.out.println("Server says " + in.readUTF());
            client.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public class TestJava {

 /**
  * @param args
  */
 public static void main(String[] args) {
  // TODO Auto-generated method stub

 }

}