Java Network Basics (Communication)

About Socket

Socket is a window that communicates with servers and clients **. ServerSocket and Socket are used for socket communication. ServerSocket package information: https://docs.oracle.com/javase/jp/7/api/java/net/ServerSocket.html Socket package information: https://docs.oracle.com/javase/jp/7/api/java/net/Socket.html

ServerSocket variable name = new ServerSocket (port number); Socket variable name = new Socket ();

These are defined and communication is performed.

Socket communication method

For simple communication

--Create an instance of ServerSocket --Socket communication connection --Communication started

Is the basic operation.

python

//ServerSocket instance
ServerSoket variable name_server_socket = new ServerSocket(port_number);

//Socket communication connection
Socket variable name_socket = new Socket();
Variable name_socket = Variable name_server_socket.accept();

//Start communication
~~Arbitrary processing~~
Variable name.close();

Server.java

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

public class Server{
    private final int port;

    // constructor
    public Server(int port){
        this.port = port;
    }
    public static void main(String[] args){
        Server server = new Server(8080);
        server.start();
    }

    public void start(){
        try{
            ServerSocket serverSocket = new ServerSocket(port);
            System.out.println("waiting for connection in this port now.");

            Socket socket = new Socket();
            socket = serverSocket.accept();
            System.out.println("connection completed.");

            socket.close();
        } catch (Exception e){
            e.printStackTrace();
        }
    }
}