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

public class ChatServer {
    boolean started = false;
    ServerSocket ss = null;
    
    List<Client> clients = new ArrayList<Client>();
    
    public static void main(String[] args) {
        new ChatServer().start();
    }
    
    public void start() {
        try {
            ss = new ServerSocket(8000);
            started = true;
        } catch (BindException e) {
            System.out.println("端口使用中....");
            System.out.println("请关掉相关程序并重新运行服务器！");
            System.exit(0);
        } catch (IOException e) {
            e.printStackTrace();
        }
        
        try {
            
            while(started) {
                Socket s = ss.accept();
                Client c = new Client(s);
System.out.println("a client connected!");
                new Thread(c).start();
                clients.add(c);
                //dis.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                ss.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
    
    class Client implements Runnable {
        private Socket s;
        private DataInputStream dis = null;
        private DataOutputStream dos = null;
        private boolean bConnected = false;
        
        public Client(Socket s) {
            this.s = s;
            try {
                dis = new DataInputStream(s.getInputStream());
                dos = new DataOutputStream(s.getOutputStream());
                bConnected = true;
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        
        public void send(String str) {
            try {
                dos.writeUTF(str);
            } catch (IOException e) {
                clients.remove(this);
                System.out.println("对方退出了！我从List里面去掉了！");
                //e.printStackTrace();
            }
        }
        
        public void run() {
            try {
                while(bConnected) {
                    String str = dis.readUTF();
System.out.println(str);
                    for(int i=0; i<clients.size(); i++) {
                        Client c = clients.get(i);
                        c.send(str);
//System.out.println(" a string send !");
                    }
                    /*
                    for(Iterator<Client> it = clients.iterator(); it.hasNext(); ) {
                        Client c = it.next();
                        c.send(str);
                    }
                    */
                    /*
                    Iterator<Client> it = clients.iterator();
                    while(it.hasNext()) {
                        Client c = it.next();
                        c.send(str);
                    }
                    */
                }
            } catch (EOFException e) {
                System.out.println("Client closed!");
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    if(dis != null) dis.close();
                    if(dos != null) dos.close();
                    if(s != null)  {
                        s.close();
                        //s = null;
                    }
                    
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
                
                
            }
        }
        
    }
}

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;

public class ChatClient extends Frame {
    Socket s = null;
    DataOutputStream dos = null;
    DataInputStream dis = null;
    private boolean bConnected = false;

    TextField tfTxt = new TextField();

    TextArea taContent = new TextArea();
    
    Thread tRecv = new Thread(new RecvThread()); 

    public static void main(String[] args) {
        new ChatClient().launchFrame(); 
    }

    public void launchFrame() {
        setLocation(400, 300);
        this.setSize(300, 300);
        add(tfTxt, BorderLayout.SOUTH);
        add(taContent, BorderLayout.NORTH);
        pack();
        this.addWindowListener(new WindowAdapter() {

            @Override
            public void windowClosing(WindowEvent arg0) {
                disconnect();
                System.exit(0);
            }
            
        });
        tfTxt.addActionListener(new TFListener());
        setVisible(true);
        connect();
        
        tRecv.start();
    }
    
    public void connect() {
        try {
            s = new Socket("127.0.0.1", 8888);
            dos = new DataOutputStream(s.getOutputStream());
            dis = new DataInputStream(s.getInputStream());
System.out.println("connected!");
            bConnected = true;
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
    }
    
    public void disconnect() {
        try {
            dos.close();
            dis.close();
            s.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
        /*
        try {
            bConnected = false;
            tRecv.join();
        } catch(InterruptedException e) {
            e.printStackTrace();
        } finally {
            try {
                dos.close();
                dis.close();
                s.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        */
    }
    
    private class TFListener implements ActionListener {

        public void actionPerformed(ActionEvent e) {
            String str = tfTxt.getText().trim();
            //taContent.setText(str);
            tfTxt.setText("");
            
            try {
//System.out.println(s);
                dos.writeUTF(str);
                dos.flush();
                //dos.close();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
            
        }
        
    }
    
    private class RecvThread implements Runnable {

        public void run() {
            try {
                while(bConnected) {
                    String str = dis.readUTF();
                    //System.out.println(str);
                    taContent.setText(taContent.getText() + str + '\n');
                }
            } catch (SocketException e) {
                System.out.println("退出了，bye!");
            } catch (EOFException e) {
                System.out.println("推出了，bye - bye!");
            } catch (IOException e) {
                e.printStackTrace();
            } 
            
        }
        
    }
}