1 import java.io.*;
  2 import java.net.*;
  3 import java.text.SimpleDateFormat;
  4 import java.util.*;
  5 import java.awt.*;
  6 import javax.swing.*;
  7 
  8 @SuppressWarnings("serial")
  9 public class Server extends JFrame {
 10     // Text area for displaying data
 11     private JTextArea jta = new JTextArea();
 12     ArrayList<Client> clients = new ArrayList<Client>();
 13     SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
 14     Date d = new Date();
 15     String time = format.format(d);
 16     // Statistics the number of clients
 17     int clientNo = 0;
 18 
 19     public static void main(String[] args) {
 20         new Server();
 21     }
 22 
 23     public Server() {
 24         // Place text area on the frame
 25         setLayout(new BorderLayout());
 26         add(new JScrollPane(jta), BorderLayout.CENTER);
 27 
 28         setTitle("Server");
 29         setSize(500, 300);
 30         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 31         setVisible(true); // It is necessary to show the frame here!
 32 
 33         ServerSocket serverSocket = null;
 34         try {
 35             // Create a server socket
 36             serverSocket = new ServerSocket(2014);
 37         } catch (IOException ex) {
 38             jta.append(" ***端口已被占用!*** " + ‘\n‘);
 39         }
 40         jta.append(" ***服务器启动时间： " + time + "***" + ‘\n‘);
 41 
 42         while (true) {
 43             Socket socket = null;
 44             try {
 45                 // Listen for a connection request
 46                 socket = serverSocket.accept();
 47             } catch (IOException e) {
 48                 e.printStackTrace();
 49             }
 50             // To display client inetAddress
 51             InetAddress inetAddress = socket.getInetAddress();
 52             clientNo++;
 53             jta.append(" Client " + clientNo + ‘\n‘);
 54             jta.append(" Host name is " + inetAddress.getHostName() + ‘\n‘);
 55             jta.append(" IP Address is " + inetAddress.getHostAddress() + ‘\n‘);
 56 
 57             // Create a new Thread for client
 58             Client task = new Client(socket);
 59             clients.add(task);
 60             new Thread(task).start();
 61         }
 62     }
 63 
 64     class Client implements Runnable {
 65         Socket socket;
 66         // Create data input and output streams
 67         DataInputStream inputFromClient = null;
 68         DataOutputStream outputToClient = null;
 69         Client c = null;
 70 
 71         public Client(Socket socket) {
 72             this.socket = socket;
 73             try {
 74                 inputFromClient = new DataInputStream(socket.getInputStream());
 75             } catch (IOException e) {
 76                 e.printStackTrace();
 77             }
 78             try {
 79                 outputToClient = new DataOutputStream(socket.getOutputStream());
 80             } catch (IOException e) {
 81                 e.printStackTrace();
 82             }
 83         }
 84 
 85         public void sentAll(String str) {
 86             try {
 87                 // Receive message from the client
 88                 outputToClient.writeUTF(str);
 89             } catch (SocketException e) {
 90                 if (c != null)
 91                     clients.remove(c);
 92             } catch (IOException e) {
 93                 e.printStackTrace();
 94             }
 95         }
 96 
 97         public void run() {
 98             try {
 99                 while (true) {
100                     // Receive sentence from the client
101                     String sentence = inputFromClient.readUTF();
102                     // Send sentence back to the client
103                     for (int i = 0; i < clients.size(); i++) {
104                         c = clients.get(i);
105                         c.sentAll(sentence);
106                     }
107 
108                     // Display to the text area
109                     jta.append(" " + time + "\n");
110                     jta.append(" " + sentence + ‘\n‘);
111                 }
112             } catch (IOException e) {
113                 // e.printStackTrace();
114                 clientNo--;
115                 if (clientNo == 0) {
116                     jta.append(" ***无客户端连接!***" + "\n");
117                     clients.remove(c); // 防止新用户使用
118                 } else {
119                     jta.append(" ***退出一用户! 剩余用户: " + clientNo + "***" + "\n");
120                 }
121             }
122         }
123     }
124 }

  1 import java.io.*;
  2 import java.net.*;
  3 import java.text.SimpleDateFormat;
  4 import java.util.Date;
  5 import java.awt.*;
  6 import java.awt.event.*;
  7 import javax.swing.*;
  8 
  9 @SuppressWarnings("serial")
 10 public class Client extends JFrame {
 11     // Text field for receiving data
 12     private JTextField jtfName = new JTextField(); // Enter Name
 13     private JTextField jtfMessage = new JTextField(); // Enter Message
 14 
 15     // Text Area to display data
 16     private JTextArea jta = new JTextArea();
 17 
 18     // Button for send massage
 19     private JButton jbSend = new JButton("Send");
 20 
 21     // IO streams
 22     private DataOutputStream toServer;
 23     private DataInputStream fromServer;
 24 
 25     public static void main(String[] args) {
 26         new Client();
 27     }
 28 
 29     public Client() {
 30         // Panel p to hold the label and text field
 31         JPanel p = new JPanel();
 32         p.setLayout(new GridLayout(2, 2));
 33         p.add(new JLabel(" Enter Name: "));
 34         p.add(jtfName);
 35         p.add(new JLabel(" Enter Message: "));
 36         p.add(jtfMessage);
 37         jtfName.setHorizontalAlignment(JTextField.LEFT);
 38         jtfMessage.setHorizontalAlignment(JTextField.LEFT);
 39 
 40         setLayout(new BorderLayout());
 41         add(p, BorderLayout.NORTH);
 42         add(new JScrollPane(jta), BorderLayout.CENTER);
 43         add(jbSend, BorderLayout.SOUTH);
 44 
 45         // Register listener for jbSend button
 46         jbSend.addActionListener(new ButtonListener());
 47 
 48         // Register listener for jtfName JTextField
 49         jtfName.addActionListener(new ButtonListener());
 50 
 51         // Register listener for jtfMessage JTextField
 52         jtfMessage.addActionListener(new ButtonListener());
 53 
 54         setTitle("Client");
 55         setSize(500, 300);
 56         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 57         setVisible(true); // It is necessary to show the frame here!
 58 
 59         try {
 60             // Create a socket to connect to the server
 61             Socket socket = new Socket("localhost", 2014);
 62 
 63             // Create an input stream to receive data from the server
 64             fromServer = new DataInputStream(socket.getInputStream());
 65 
 66             // Create an output stream to send data to the server
 67             toServer = new DataOutputStream(socket.getOutputStream());
 68 
 69             // Receive data from the server all the time
 70             while (true) {
 71                 // read data from client
 72                 String sentence = fromServer.readUTF();
 73                 SimpleDateFormat format = new SimpleDateFormat(
 74                         "yyyy-MM-dd HH:mm:ss");
 75                 Date d = new Date();
 76                 String time = format.format(d);
 77 
 78                 // Display to the text area
 79                 jta.append(" " + time + "\n");
 80                 jta.append(" " + sentence + "\n");
 81             }
 82         } catch (IOException ex) {
 83             jta.append(" ***服务器连接失败!***" + ‘\n‘);
 84         }
 85     }
 86 
 87     private class ButtonListener implements ActionListener {
 88         public void actionPerformed(ActionEvent e) {
 89             try {
 90                 // Get the Name and Message from the text field
 91                 String Name = jtfName.getText().trim();
 92                 String Message = jtfMessage.getText().trim();
 93                 // Prevent send a blank message
 94                 if (Name != null && Name.length() != 0 && Message != null
 95                         && Message.length() != 0) {
 96                     String data = Name + "： " + Message;
 97 
 98                     // Send the data to the server
 99                     toServer.writeUTF(data);
100                     toServer.flush();
101                 } else
102                     jta.append(" ***警告：名称和内容均不能为空!*** " + "\n");
103 
104             } catch (IOException ex) {
105                 System.err.println(ex);
106             }
107         }
108     }
109 }