public void BuildServer() {try {int port=9900;server = new ServerSocket(port);System.out.println("创建群聊服务器成功！");InetAddress addr=InetAddress.getLocalHost();System.out.println("本机地址："+addr); //将网络地址和端口打印方便客户端进行连接System.out.println("端口号："+port);} catch (IOException e) {e.printStackTrace();}}

    @Override   //这是重写Thread类中的run();public void run() {while (true) {try {Socket socket = server.accept();                 //链接建立后，接收客户端传来的用户名信息DataInputStream in = new DataInputStream(socket.getInputStream());String name=in.readUTF();if (name.equals(""))name="匿名用户";System.out.println(name + "已成功连接！");try {DataOutputStream out = new DataOutputStream(socket.getOutputStream());out.writeUTF(("亲爱的"+name+",你已连接到服务器！\n\r"));} catch (IOException e) {e.printStackTrace();}                //这是一个线程类，之后将会创建，用于与客户端收发消息GroupThread gt = new GroupThread(socket, list, name);                //list是一个链表，存储每个已存在的连接，其初始化：ArrayList<GroupThread> list = new ArrayList<GroupThread>();list.add(gt);gt.start();} catch (IOException e) {}}

public class GroupServer extends Thread {/*** @param 群聊服务器*/ServerSocket server;ArrayList<GroupThread> list = new ArrayList<GroupThread>();public void BuildServer() {}@Overridepublic void run() {}public static void main(String[] args) {GroupServer s = new GroupServer();s.BuildServer();s.start();}}

public class GroupThread extends Thread{Socket socket;String str;String accept;ArrayList<GroupThread> list;private String username;public  GroupThread(Socket socket, ArrayList<GroupThread> list,String name){this.socket=socket;this.list=list;this.username=name;}@SuppressWarnings("deprecation")
public void run(){while (true) {try {DataInputStream in = new DataInputStream(socket.getInputStream());accept=in.readUTF();if(!accept.equals("")){sendGroup();}} catch (IOException e) {try {               //客户端关闭后断开连接，将这个链接从链表中移除，并停止线程System.out.println(username+"已断开连接!");list.remove(list.indexOf(this));this.stop();socket.close();} catch (IOException e1) {System.out.println("断开连接出现异常！");}}} }private void sendGroup() {int index=list.indexOf(this);for(int i=0;i<list.size();i++){if(index!=i){list.get(i).Send(accept);}}public void Send(String str){        try {            DataOutputStream out = new DataOutputStream(                    socket.getOutputStream());            out.writeUTF(str);        } catch (IOException e) {            e.printStackTrace();        }    }
}

public class Login extends JFrame {private static final long serialVersionUID = 1L;private JTextField name = new JTextField(9);private JButton login = new JButton("登录");public void showUI() {this.setTitle("请输入你的用户名");this.setSize(300, 240);this.setDefaultCloseOperation(EXIT_ON_CLOSE);this.setLocationRelativeTo(null);this.setLayout(new FlowLayout());this.setResizable(false);this.add(new JLabel("用户名："));this.add(name);Listener listener=new Listener(this,name);name.addKeyListener(listener);this.add(login);login.setFocusable(false);login.addActionListener(listener);this.setVisible(true);}public static void main(String[] args) {new Login().showUI();}
}class Listener implements KeyListener,ActionListener{Login login;JTextField jt;private String name;public Listener(Login login,JTextField jt){this.jt=jt;this.login=login;}@Overridepublic void actionPerformed(ActionEvent e) {name=jt.getText();MyChat chat=new MyChat(name);try {chat.runit();} catch (IOException e1) {e1.printStackTrace();}login.setVisible(false);}@Overridepublic void keyTyped(KeyEvent e) {}@Overridepublic void keyPressed(KeyEvent e) {}@Overridepublic void keyReleased(KeyEvent e) {if(e.getKeyCode()==10){name=jt.getText();MyChat chat=new MyChat(name);try {chat.runit();} catch (IOException e1) {e1.printStackTrace();}login.setVisible(false);}}}

public class MyChat extends Thread {JButton send = new JButton("发送");JTextField jt = new JTextField(20);JTextArea jta = new JTextArea();DataOutputStream out;Socket socket;String str;byte secret=19;String name;ServerSocket server;JFrame thiss = new JFrame();public MyChat(String name){this.name=name;}public void client() throws IOException {thiss.setSize(400, 300);thiss.setLayout(new BorderLayout());thiss.setDefaultCloseOperation(3);thiss.setLocationRelativeTo(null);JScrollPane js = new JScrollPane(jta);thiss.getContentPane().add(js);thiss.setResizable(false);JPanel south = new JPanel();thiss.add(south, BorderLayout.SOUTH);south.add(jt);send.setFocusable(false);jta.setFocusable(false);jt.addKeyListener(new KeyListener() {@Overridepublic void keyTyped(KeyEvent e) {}@Overridepublic void keyReleased(KeyEvent e) {}@Overridepublic void keyPressed(KeyEvent e) {if (KeyEvent.getKeyText(e.getKeyCode()).equals("Enter")) {str = jt.getText() + "\n\r";jt.setText("");jta.append(name +"：" + str);try {out = new DataOutputStream(socket.getOutputStream());out.writeUTF(name +"：" + str);} catch (IOException e1) {}};}});send.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent actionEvent) {str = jt.getText() + "\n\r";jt.setText("");jta.append(name+"：" + str);try {out = new DataOutputStream(socket.getOutputStream());out.writeUTF((name + "：" + str));} catch (IOException e) {}}});south.add(send);thiss.setVisible(true);}@SuppressWarnings("deprecation")public void run() {while (true) {try {DataInputStream in = new DataInputStream(socket.getInputStream());String accept = in.readUTF();if(!accept.equals(""))jta.append(accept);} catch (IOException e) {try {System.out.println("连接已断开！");socket.close();this.stop();} catch (IOException e1) {e1.printStackTrace();}} }}public void connect() {try {String addr="127.0.0.1";//本机地址socket = new Socket(addr, 9900);out = new DataOutputStream(socket.getOutputStream());out.writeUTF(name);thiss.setTitle(name);} catch (IOException e) {}}public void runit() throws IOException{this.client();this.connect();this.start();if(name.equals("")){name="匿名";thiss.setTitle("匿名");}}
}