Client.java

import java.io.IOException;
import java.io.BufferedReader;
import java.io.PrintWriter;
import java.io.InputStreamReader;

import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

public class Client {

    public static void main(String[] args) throws UnknownHostException, IOException, ClassNotFoundException, InterruptedException {
        InetAddress host = InetAddress.getLocalHost();
        int serverPort = 9090;
        Socket serverConnection = new Socket(host.getHostName(), serverPort);

        BufferedReader receiver = new BufferedReader(new InputStreamReader(serverConnection.getInputStream()));
        PrintWriter sender = new PrintWriter(serverConnection.getOutputStream(), true);

        while(true) {
            sender.println("10 20 30 40");
            String response = receiver.readLine();
            System.out.println("Response: " + response);
        }
    }
}

Server.java

import java.io.IOException;
import java.io.BufferedReader;
import java.io.PrintWriter;
import java.io.InputStreamReader;

import java.lang.ClassNotFoundException;
import java.net.ServerSocket;
import java.net.Socket;

import java.util.*;

public class Server {

    public static void main(String[] args)  throws IOException, ClassNotFoundException {
        ServerSocket server = new ServerSocket(9090);
        try {
            while (true) { 
                Socket clientConnection = server.accept();
                ClientHandler t = new ClientHandler(clientConnection);
                t.start();
            }
        } catch (Exception e) {
            server.close();
        }
    }

}

class ClientHandler extends Thread {

    private Socket s;
    private BufferedReader receiver;
    private PrintWriter sender;

    public ClientHandler(Socket s) {
        this.s = s; 
        try {
            this.receiver = new BufferedReader(new InputStreamReader(this.s.getInputStream()));
            this.sender = new PrintWriter(this.s.getOutputStream(), true);
        } catch (Exception e) {
            e.printStackTrace();
        }
    } 

    @Override
    public void run() {
        while (true) { 
            try {
                String request = this.receiver.readLine();
                System.out.println("Request: " + request);
                String[] nums = request.split(" ");
                int sum = 0;
                for(int i = 0; i < nums.length; i ++) {
                    sum += Integer.parseInt(nums[i]);
                }
                String response = String.valueOf(sum);
                this.sender.println(response);
            } catch (Exception e) {
                break;
            }
        }
        try { 
            this.receiver.close(); 
            this.sender.close(); 
            
        }catch(IOException e){ 
            e.printStackTrace(); 
        }
    } 

}

Server_Blocking.java

import java.io.IOException;
import java.io.BufferedReader;
import java.io.PrintWriter;
import java.io.InputStreamReader;

import java.lang.ClassNotFoundException;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {

    public static void main(String[] args)  throws IOException, ClassNotFoundException {
        ServerSocket server = new ServerSocket(9090);
        Socket clientConnection = server.accept();
    
        BufferedReader receiver = new BufferedReader(new InputStreamReader(clientConnection.getInputStream()));
        PrintWriter sender = new PrintWriter(clientConnection.getOutputStream(), true);
    
        try {
            while(true) {
                String request = receiver.readLine();
                String[] nums = request.split(" ");
                int sum = 0;
                for(int i = 0; i < nums.length; i ++) {
                    sum += Integer.parseInt(nums[i]);
                }
                String response = String.valueOf(sum);
                sender.println(response);
            }
        } catch (Exception e) {
            server.close();
        }
    }
}

javac Server.java && java Server để chạy server

javac Client.java && java Client để chạy client