How to Make a Server to Allow the Connection to the Socket 6123 in Java?

Last Updated : 11 Nov, 2020

A socket connection means the two machines have information about each other’s network location (IP Address) and TCP port. The java.net.Socket class represents a Socket. Here, we are going to look at the approach of connecting to socket 6123.

Approach:

Create an object of Socket class and pass 6123 as an argument.
Accept connections with accept() method of ServerSocket class.
Get the address of the connection with getInetAddress() method of Socket class and getHostAddress() of InetAddress class.

Server Code:

Java

// Make a server to allow the connection to the socket 6123

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

public class Server {
    public static void main(String[] args) { check(); }
    private static void check()
    {
        try {
            // Creating object of ServerSocket class
            ServerSocket connection
                = new ServerSocket(6123);
          
            while (true) {
                System.out.println("Listening");

                // Creating object of Socket class
                Socket socket = connection.accept();

                // Creating object of InetAddress class
                InetAddress address
                    = socket.getInetAddress();
              
                System.out.println(
                    "Connection made to "
                    + address.getHostAddress());
                pause(1000);
                  
                  // close the socket
                socket.close();
            }
        }
        catch (IOException e) {
            System.out.println("Exception detected: " + e);
        }
    }
    private static void pause(int ms)
    {
        try {
            Thread.sleep(ms);
        }
        catch (InterruptedException e) {
        }
    }
}

Output

Client Code:

Java

// A Java program for a Client

import java.net.*;
import java.io.*;

public class Client {
    // initialize socket and input output streams
    private Socket socket = null;
    private DataInputStream input = null;
    private DataOutputStream out = null;

    // constructor to put ip address and port
    public Client(String address, int port)
    {
        // establish a connection
        try {
            socket = new Socket(address, port);
            System.out.println("Connected");

            // takes input from terminal
            input = new DataInputStream(System.in);

            // sends output to the socket
            out = new DataOutputStream(
                socket.getOutputStream());
        }
        catch (UnknownHostException u) {
            System.out.println(u);
        }
        catch (IOException i) {
            System.out.println(i);
        }

        // string to read message from input
        String line = "";

        // keep reading until "Over" is input
        while (!line.equals("Over")) {
            try {
                line = input.readLine();
                out.writeUTF(line);
            }
            catch (IOException i) {
                System.out.println(i);
            }
        }

        // close the connection
        try {
            input.close();
            out.close();
            socket.close();
        }
        catch (IOException i) {
            System.out.println(i);
        }
    }

    public static void main(String args[])
    {
        Client client = new Client("127.0.0.1", 6123);
    }
}