服务段

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;

public class Main {
    private BufferedReader reader;//流
    private ServerSocket server;//
    private Socket socket;//套接字
    void getServer(){//此方法完成服务端的各种必要链接
        try {
            server = new ServerSocket(8997);//实例化Socket对象，并给他个8997端口
            System.out.println("服务器套接字创建成功");
            while (true){
                System.out.println("等待客户端连接");
                socket = server.accept();
                reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));//实例化BufferedReader对象
                getClientMessage();//调用getClientMessage方法
            }
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    private void getClientMessage(){//此方法持续收听客户端信息
        try {
            while (true){
                System.out.println("客户机:" + reader.readLine());//获取客户端信息
            }
        }catch (Exception e){
            e.printStackTrace();
        }

        try {
            if (reader != null){
                reader.close();//关闭流
            }
            if (socket != null){
                socket.close();//关闭套接字
            }
        }catch (IOException e){
            e.printStackTrace();
        }

    }
    public static void main(String[] args) {
    // write your code here
        Main ma = new Main();
        ma.getServer();
    }
}

客户端

package com.company;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.PrintWriter;
import java.net.Socket;

public class users extends JFrame {
    private PrintWriter writer;
    Socket socket;//创建字节套对象
    private JTextArea ta = new JTextArea();
    private JTextField tf = new JTextField();
    Container cc;
    public users(String title){//设置jframe窗体，不是特别重要
        super(title);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        cc = this.getContentPane();
        final JScrollPane scrollPane = new JScrollPane();
        getContentPane().add(scrollPane,BorderLayout.CENTER);
        scrollPane.setViewportView(ta);
        cc.add(tf,"South");


        tf.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                writer.println(tf.getText());//写入流，服务器那边是读取流
                ta.append(tf.getText() + "\n");//把文本框信息写在文本域zon
                ta.setSelectionEnd(ta.getText().length());
                tf.setText("");
            }
        });
    }
    private void connect(){//连接服务端
        ta.append("尝试链接\n");
        try {
            socket = new Socket("127.0.0.1",8997);//连接本地服务器，并指定与服务器相同的端口
            writer = new PrintWriter(socket.getOutputStream(),true);//打印内容到控制台
            ta.append("完成连接\n");

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

    public static void main(String[] args) {
        users mm = new users("客户端");
        mm.setSize(400,200);
        mm.setVisible(true);
        mm.connect();
    }
}