Server side:

1. Create ServerSocket object and bind listening port;

2. Listen to the client request through the accept() method;

3. Read the request information sent by the client through the input stream after the connection is established;

4. Send response information to client through output;

package com.wxd.socket;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * Socket communication based on TCP protocol realizes user login and server
 */
public class Server {
    public static void main(String[] args) {
        try {
            //Server side
            //1,Create a server Socket，I.e ServerSocket，Specify the bound port and listen for it
            ServerSocket serverSocket =new ServerSocket(10086);//1024-65535 A port of
            //2,call accept()Method to start listening and wait for the client to connect
            Socket socket = serverSocket.accept();
            //3,Get the input stream and read the client information
            InputStream is = socket.getInputStream();
            InputStreamReader isr =new InputStreamReader(is);
            BufferedReader br =new BufferedReader(isr);
            String info =null;
            while((info=br.readLine())!=null){
                System.out.println("I am the server, and the client says:"+info);
            }
            socket.shutdownInput();//Close input stream
            //4,Get the output stream in response to the client's request
            OutputStream os = socket.getOutputStream();
            PrintWriter pw = new PrintWriter(os);
            pw.write("Welcome!");
            pw.flush();
            //5,close resource
            pw.close();
            os.close();
            br.close();
            isr.close();
            is.close();
            socket.close();
            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Console output:

I am the server, and the client says: user name: admin; password: 123

client:

1. Create a socket object, indicating the server address and port number to be connected;

2. After establishing the connection, send the request information to the server through the output;

3. Obtain the response information of the server through the input stream;

4. Close related resources;

package com.wxd.socket;

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

/**
 * Socket communication based on TCP protocol and Realization of client
 */
public class Client {
    public static void main(String[] args) {
        try {
            //client
            //1,Create client Socket，Specify server address and port
            Socket socket =new Socket("localhost",10086);
            //2,Get the output stream and send information to the server
            OutputStream os = socket.getOutputStream();//Byte output stream
            PrintWriter pw =new PrintWriter(os);//Wrap the output stream as a print stream
            pw.write("user name: admin；Password: 123");
            pw.flush();
            socket.shutdownOutput();
            //3,Get the input stream and read the response information on the server side
            InputStream is = socket.getInputStream();
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            String info = null;
            while((info=br.readLine())!=null){
                System.out.println("I am the client and the server says:"+info);
            }
            //4,close resource
            br.close();
            is.close();
            pw.close();
            os.close();
            socket.close();
        }catch(IOException e){
            e.printStackTrace();
        }
    }
}

Console output:

I am the client, the server said: Welcome!

Process finished with exit code 0