Socket sample Java

gistfile1.txt

Compile client and server and then start server as follows:

$ java GreetingServer 6066
Waiting for client on port 6066...
Check client program as follows:

Start client :
$ java GreetingClient localhost 6066
Connecting to localhost on port 6066
Just connected to localhost/127.0.0.1:6066
Server says Thank you for connecting to /127.0.0.1:6066
Goodbye!

GreetingClient.java

// File Name GreetingClient.java

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

public class GreetingClient {

	public static void main(String[] args) {

		String serverName = args[0];

		int port = Integer.parseInt(args[1]);

		try {

			System.out.println("CLIENT: Connecting to " + serverName + " on port " + port);

			Socket client = new Socket(serverName, port);

			System.out.println("CLIENT: Just connected to " + client.getRemoteSocketAddress());

			OutputStream outToServer = client.getOutputStream();

			final DataOutputStream out = new DataOutputStream(outToServer);
			out.writeUTF("Hello from client " + client.getLocalSocketAddress());

			InputStream inFromServer = client.getInputStream();
			DataInputStream in = new DataInputStream(inFromServer);

			String msg = in.readUTF();
			System.out.println("SERVER: " + msg);

			final Scanner scanIn = new Scanner(System.in);

			new Thread() {

				public void run() {

					while (true) {

						System.out.println("Enter message  : ");
						String sWhatever = scanIn.nextLine();
						try {
							out.writeUTF("\"" + sWhatever + "\"");
						} catch (IOException e) {

							System.out.println("SERVER: left\nGAME OVER ");
						}
					}

				};
			}.start();

			while (!msg.equalsIgnoreCase("q")) {

				msg = in.readUTF();

				System.out.println("SERVER: " + msg);

				if (!msg.startsWith(" I received  ")) {
					
					out.writeUTF(" I received  \"" + msg.replace("\"", "") + "\"");
				}
			}

			System.out.println("SERVER: left\nGAME OVER ");

			scanIn.close();
			client.close();

		} catch (IOException e) {

			System.out.println("SERVER: left\nGAME OVER ");

			// e.printStackTrace();
		}
	}
}

GreetingServer.java

// File Name GreetingServer.java

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

public class GreetingServer extends Thread {

	private ServerSocket serverSocket;

	public GreetingServer(int port) throws IOException {

		serverSocket = new ServerSocket(port);

		serverSocket.setSoTimeout(1000000);
	}

	public void run() {

		final Scanner scanIn = new Scanner(System.in);

		while (true) {

			try {

				System.out.println("SERVER: Waiting for client on port " + serverSocket.getLocalPort() + "...");
				Socket server = serverSocket.accept();

				System.out.println("SERVER: " + "Game start");

				System.out.println("SERVER: Just connected to " + server.getRemoteSocketAddress());
				final DataInputStream in = new DataInputStream(server.getInputStream());

				System.out.println("CLIENT: " + in.readUTF());
				
				final DataOutputStream out = new DataOutputStream(server.getOutputStream());
				out.writeUTF("Thank you for connecting to " + server.getLocalSocketAddress() + "\n..Welcome...!");

				new Thread() {

					public void run() {

						try {
							while (true) {
								String msg = in.readUTF();
								
								if(!msg.startsWith(" I received  ")) {
									
									out.writeUTF(" I received  \"" + msg.replace("\"", "")  + "\"");
								}
								
								System.out.println("CLIENT: " + msg);
							}
						} catch (IOException e) {
							// TODO Auto-generated catch block
							System.out.println("CLIENT closed");
						}
					};
				}.start();

				System.out.println("Enter message : ");
				String sWhatever = scanIn.nextLine();

				while (!sWhatever.equalsIgnoreCase("q")) {

					System.out.println("SERVER: " + sWhatever);
					out.writeUTF("\"" + sWhatever + "\"");

					System.out.println("Enter message : ");
					sWhatever = scanIn.nextLine();
				}

				out.writeUTF("q");
				server.close();

				System.out.println("SERVER: Closed" + "Game over");
			} catch (SocketTimeoutException s) {

				System.out.println("Socket timed out!");
				break;

			} catch (IOException e) {
				System.out.println("SERVER: Closed" + "Game over");
				break;
			}
		}

		scanIn.close();
	}

	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();
		}
	}
}