Socket completes the chat program.

Thinking analysis

If you use tcp, you need to create a server to forward various information. The server must be able to accept the information sent by the client and forward it to the specified object according to the object sent.
Need to create multiple threads, the client must bind a listener event, can send Socket, and then can receive information from the server.

Server code

import javax.swing.;
import java.io.;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.*;

public class Server extends JFrame implements Runnable {
private Socket socket = null;
private ServerSocket serverSocket = null;
private List list = new ArrayList();
private Map<Integer,Socket> map = new HashMap();//储存多个客户端的线程。
public static Map mapSocket = new HashMap();
private int i = 0;

private BufferedReader bufferedReader = null;
public Server(){
    this.setTitle("服务器");
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置默认关闭方式
    this.setSize(300,300);
    this.setVisible(true);
    try {
        serverSocket= new ServerSocket(9999);//设置服务端的端口
    } catch (IOException e) {
        e.printStackTrace();
    }

    new Thread(this).start();
}



@Override
public void run() {


        try {
            while(true){
            socket = serverSocket.accept();//为的是为了多个客户端服务
            System.out.println("连接成功");
            //InetAddress inetAddress =  socket.getLocalAddress();
           // System.out.println("地址"+inetAddress.getHostAddress());
                map.put(i,socket);
            ChatThread chatThread = new ChatThread(socket,map);
            list.add(chatThread);
           //  name = mapSocket.get(socket).toString();
           //  System.out.println("我的名字是"+name+"请求连接");

            i++;
            People.id++;
                System.out.println("我是people Id"+People.id);

            chatThread.start();

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

}

class ChatThread extends Thread{
    InputStream in = null;


    private Socket socket = null;
    private BufferedReader bufferedReader = null;
    private PrintWriter printWriter = null;
    private String str;
    ObjectInputStream ois = null;
    public ChatThread(Socket socket,Map<Integer,Socket> map){//接受信息，和转发信息
        System.out.println("服务客户的线程启动");
        this.str = str;
        this.socket = socket;
        try {
            in = socket.getInputStream();
            ois = new ObjectInputStream(in);//这个也是包裹的

          //  bufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));

           // printWriter = new PrintWriter(socket.getOutputStream(),true);



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

    }

    @Override
    public void run() {
        String name = null;
        String name2 = null;
        String[] nameArray = new String[3];
        while (true){
            try {
                Msg msg = (Msg)ois.readObject();
                System.out.println();
               // String str = bufferedReader.readLine();//读取客户端来的信息。
                Socket target = map.get(msg.getI());
                System.out.println("发送给"+msg.getI());
                OutputStream outputStream = target.getOutputStream();
                ObjectOutputStream oos = new ObjectOutputStream(outputStream);
                oos.writeObject(msg);

                //sendMessage(str,name2);//根据信息，发往指定的地方。
            } catch (IOException e) {
                e.printStackTrace();
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }
        }
    }

    public void sendMessage(String msg,String name2){



    }
}

Client code

import javax.swing.;
import java.awt.;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.*;
import java.net.Socket;
import java.util.HashMap;
import java.util.Map;

public class Client extends JFrame implements Runnable {
private JTextArea ta = new JTextArea();
private JTextField tf = new JTextField();
private String name = null;
private InputStream in = null;
OutputStream os = null;
ObjectOutputStream oos = null;
ObjectInputStream oi = null;
int id = 0;

@Override
public String getName() {
    return name;
}

@Override
public void setName(String name) {
    this.name = name;
}

private String name2 = null;


private Socket socket = null;
public Client(String name,String name2,int id){
    this.add(ta,BorderLayout.CENTER);
    this.add(tf,BorderLayout.SOUTH);
    this.name2 = name2;
    this.id = id;

    this.setTitle(name);
    this.name = name;


    tf.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            try {

// PrintWriter printWriter = new PrintWriter(socket.getOutputStream(),true);
// printWriter.println(name+":"+tf.getText()+":"+name2);

                Msg msg = new Msg();
                msg.setI(id);
                System.out.println("我设置了id"+id);
                msg.setContent(tf.getText());
                msg.setName(name);
                msg.setName2(name2);
                ta.append(name+":"+tf.getText()+"\n");
                oos.writeObject(msg);//发送信息
                tf.setText("");
            } catch (IOException ex) {
                ex.printStackTrace();
            }

        }
    });
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.setSize(300,300);
    this.setVisible(true);
    try {
        socket = new Socket("127.0.0.1",9999);
        os = socket.getOutputStream();
        oos = new ObjectOutputStream(os);


    } catch (IOException e) {
        e.printStackTrace();
    }
    Server.mapSocket.put(socket,"123");
    new Thread(this).start();

}

@Override
public void run() {
    try {
        while(true) {
            //BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));//目的是读取sock发来的信息
            //System.out.println("我运行了");
           // String s = bufferedReader.readLine();
            try {
                in = socket.getInputStream();//每次调用的时候，创建连接。不写在这里就不行。
                oi = new ObjectInputStream(in);
                Msg msg = (Msg)oi.readObject();;//接收连接
                System.out.println(msg.getContent());
                ta.append( msg.getName()+":"+msg.getContent()+"\n");
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }

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

}

}

Display interface (plus call)

import javax.swing.;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import java.awt.;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.List;

public class ShowPeople extends JFrame implements ActionListener { private String name = null ;//Select the object to communicate.

@Override
public String getName() {
    return name;
}

@Override
public void setName(String name) {
    this.name = name;
}

public ShowPeople(){
    String  name4=JOptionPane.showInputDialog("输入昵称：");
    UserDao userDao = new UserDao();
    List list = userDao.showUser();
    JButton[] buttons = new JButton[list.size()];
    String[] columnName = {"名字","性别"};
    String[][] tableVlues =  new String[list.size()][2];
    for(int i = 0;i<list.size();i++){
        tableVlues[i][0] = list.get(i).toString();

        tableVlues[i][1] = "";
    }

    JTable jTable = new JTable(tableVlues,columnName);
    jTable.getSelectionModel().addListSelectionListener(new ListSelectionListener() {
        int i = 0;

        @Override
        public void valueChanged(ListSelectionEvent listSelectionEvent) {
            i++;
            int row = jTable.getSelectedRow();
            int column = jTable.getSelectedColumn();
             name = jTable.getValueAt(row,column).toString();
             dispose();
             if(i == 1){//因为每次点击JTable会运行两次，所以为了防止运行两次。
                 int id = 0;
                 People.map.put(name4,id);//People中的map是记录名字和id，因为服务器每次连接，就会使用i于这个socket绑定，然后i++。
                 id++;
                 People.map.put(name,id);
                 id++;
                 int id2 = (int)People.map.get(name);
                 int id3 = (int)People.map.get(name4);
                 Client client =  new Client(name4,name,id2);//最后面的那个参数是要建立通讯的id标识
                 Client client1 = new Client(name,name4,id3);
             }
        }
    });
    JScrollPane scrollPane = new JScrollPane(jTable);
    getContentPane().add(scrollPane,BorderLayout.CENTER);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.setSize(300,300);
    this.setVisible(true);
}
public static void main(String[] args) {
    new ShowPeople();
}
@Override
public void actionPerformed(ActionEvent actionEvent) {

}

}

Effect display (there is a connection to the database, so there is data)

Click on one of the names.