Java network communication over TCP socket

net_tcp_receiver.java

Directories to net_tcp_receiver.java in the repository: java/cz/petrfaltus/net

package cz.petrfaltus.net;

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

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

import static java.lang.System.out;

public class net_tcp_receiver {
    private static final int RECEIVER_PORT = 10000;
    private static final int RECEIVED_MESSAGES_MAX = 10;

    public static void main(String[] args) {
        out.println("TCP IPv4 stream socket receiver");

        try {
            ServerSocket socket = new ServerSocket(RECEIVER_PORT, RECEIVED_MESSAGES_MAX);
            out.println("- socket created, bound on port " + RECEIVER_PORT + " and is listening for max " + RECEIVED_MESSAGES_MAX + " messages");

            boolean stop = false;
            while (stop == false) {
                Socket msgsock = socket.accept();
                out.println("- socket accepted request");

                InetAddress peer = msgsock.getInetAddress();
                InetAddress local = msgsock.getLocalAddress();
                out.println("- peer connect from " + peer.getHostAddress() + ":" + msgsock.getPort() + " on " + local.getHostAddress() + ":" + msgsock.getLocalPort());

                InputStreamReader isr = new InputStreamReader(msgsock.getInputStream());
                BufferedReader br = new BufferedReader(isr);

                String msg = br.readLine();
                out.println("- message " + msg.length() + "B received");
                out.println("|" + msg + "|");

                if (msg.equals("stop")) {
                    // received message "stop" to stop the receiver
                    stop = true;
                }

                msgsock.close();
                out.println("- socket closed request");
            }

            socket.close();
            out.println("- socket closed");
        } catch (IOException e) {
            out.println("- " + e);
        }
    }
}

net_tcp_sender.java

package cz.petrfaltus.net;

import java.io.IOException;
import java.io.PrintStream;

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

import java.text.DateFormat;
import java.text.SimpleDateFormat;

import java.util.Date;

import static java.lang.System.out;

public class net_tcp_sender {
    private static final String RECEIVER_ADDRESS = "127.0.0.1";
    private static final int RECEIVER_PORT = 10000;

    public static void main(String[] args) {
        out.println("TCP IPv4 stream socket sender");

        try {
            Socket socket = new Socket(RECEIVER_ADDRESS, RECEIVER_PORT);
            out.println("- socket created for sending to " + RECEIVER_ADDRESS + ":" + RECEIVER_PORT);

            InetAddress peer = socket.getInetAddress();
            InetAddress local = socket.getLocalAddress();
            out.println("- for " + peer.getHostAddress() + ":" + socket.getPort() + " bound on " + local.getHostAddress() + ":" + socket.getLocalPort());

            PrintStream output_stream = new PrintStream(socket.getOutputStream());

            String msg;
            if (args.length > 0) {
                msg = args[0]; // message is the first parameter, for example "stop" to stop the receiver
            } else {
                Date now = new Date();
                DateFormat date_format = new SimpleDateFormat("d.M.yyyy 'in' H:mm:ss");

                msg = "This is Java message sent at " + date_format.format(now);
            }
            out.println("|" + msg + "|");

            output_stream.print(msg);
            out.println("- message " + msg.length() + "B sent");

            output_stream.close();
            socket.close();
            out.println("- socket closed");
        } catch (IOException e) {
            out.println("- " + e);
        }
    }
}

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