Java Socket Server-Client Example

First create a new Java Project in Android Eclipse

then Create   a Class Name 1)    SocketServerExample.java

Code For this class.........................



public class SocketServerExample {
    //static ServerSocket variable
    private static ServerSocket server;
    //socket server port on which it will listen
    private static int port = 9876;
    
    public static void main(String args[]) throws IOException, ClassNotFoundException{
        //create the socket server object
        server = new ServerSocket(port);
        //keep listens indefinitely until receives 'exit' call or program terminates
        while(true){
            System.out.println("Waiting for client request");
            //creating socket and waiting for client connection
            Socket socket = server.accept();
            //read from socket to ObjectInputStream object
            ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());
            //convert ObjectInputStream object to String
            String message = (String) ois.readObject();
            System.out.println("Message Received: " + message);
            //create ObjectOutputStream object
            ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());
            //write object to Socket
            oos.writeObject("Hi Client "+message);
            //close resources
            ois.close();
            oos.close();
            socket.close();
            //terminate the server if client sends exit request
            if(message.equalsIgnoreCase("exit")) break;
        }
        System.out.println("Shutting down Socket server!!");
        //close the ServerSocket object
        server.close();
    }
    
} 



And Create a Client Class

2)SocketClientExample.java



public class SocketClientExample {
     public static void main(String[] args) throws UnknownHostException, IOException, ClassNotFoundException, InterruptedException{
            //get the localhost IP address, if server is running on some other IP, you need to use that
            InetAddress host = InetAddress.getLocalHost();
            Socket socket = null;
            ObjectOutputStream oos = null;
            ObjectInputStream ois = null;
            for(int i=0; i<5;i++){
                //establish socket connection to server
                socket = new Socket(host.getHostName(), 9876);
                //write to socket using ObjectOutputStream
                oos = new ObjectOutputStream(socket.getOutputStream());
                System.out.println("Sending request to Socket Server");
                if(i==4)oos.writeObject("exit");
                else oos.writeObject(""+i);
                //read the server response message
                ois = new ObjectInputStream(socket.getInputStream());
                String message = (String) ois.readObject();
                System.out.println("Message: " + message);
                //close resources
                ois.close();
                oos.close();
                Thread.sleep(100);
            }
        }
} 



Then first  run the Server class after run client class.

the out put will be in Java console..............................




Sending request to Socket Server
Message: Hi Client 0
Sending request to Socket Server
Message: Hi Client 1
Sending request to Socket Server
Message: Hi Client 2
Sending request to Socket Server
Message: Hi Client 3
Sending request to Socket Server
Message: Hi Client exit