UDP协议实现简单的聊天室

本案例采用了ufg-8的语言格式，涉及到了io，多线程，GUI等知识。

package test02.ChatTest;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;

public class GuiChat extends JFrame {
    private JButton sendButton;     //发送按钮
    private JButton clearButton;      //清除聊天记录按钮
    private static int DEFAULT_PORT=8888;    //设置的初始端口号
    private JTextField ipTextField;   //输入ip地址的文本框
    private JTextField portTextField;   //输入端口号的文本框
    private JTextArea inputTextArea;    //输入要说的话的地方
    private JTextArea centerTextArea;   //显示聊天记录的区域
    private JLabel stateLB;             //设置端口状态信息
    private DatagramSocket datagramSocket;


        public GuiChat(){
            setUpUI();
            setListener();
            initSocket();
        }
        public void setUpUI(){
            //设置窗口的基本属性
            setTitle("GUI聊天室");
            setLayout(new BorderLayout());
            setBounds(400,300,700,600);
            setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
            setVisible(true);

            //设置窗口上方的提示信息
            stateLB=new JLabel();
            stateLB.setText("窗口还未开始监听");
            stateLB.setHorizontalAlignment(JLabel.RIGHT);
            add(stateLB,BorderLayout.NORTH);

            //设置显示聊天记录的部分
            centerTextArea=new JTextArea();
            centerTextArea.setEditable(false);        //不可以对聊天记录进行修改
            centerTextArea.setBackground(Color.cyan);
            add(new JScrollPane(centerTextArea),BorderLayout.CENTER);

            //设置窗口下方的输入框和ip地址和端口输入框
            JPanel southPanel=new JPanel();
            southPanel.setLayout(new BorderLayout());
            inputTextArea=new JTextArea(5,30);
            southPanel.add(inputTextArea,BorderLayout.NORTH);

            JPanel bottomPanel=new JPanel();
            ipTextField=new JTextField("127.0.0.1",10);
            portTextField=new JTextField(String.valueOf(DEFAULT_PORT),3);
            sendButton=new JButton("发送");
            clearButton=new JButton("清空");
            bottomPanel.add(ipTextField);
            bottomPanel.add(portTextField);
            bottomPanel.add(sendButton);
            bottomPanel.add(clearButton);
            southPanel.add(bottomPanel,BorderLayout.SOUTH);
            add(southPanel,BorderLayout.SOUTH);

            //使窗口可视化
            setResizable(false);
        }
        //设置各个监听事件
        public void setListener(){
            sendButton.addActionListener(new ActionListener(){
                public void actionPerformed(ActionEvent e){
                    String ipAddress=ipTextField.getText();
                    String remotePort=portTextField.getText();
                    if(ipAddress==null||ipAddress.trim().equals("")
                            ||remotePort==null||remotePort.trim().equals("")){
                        JOptionPane.showMessageDialog(GuiChat.this,"你得端口和ip地址都输里面呀");
                    }
                    if(datagramSocket==null||datagramSocket.isClosed()){
                        JOptionPane.showMessageDialog(GuiChat.this,"监听端口失败啦");
                        return;
                    }
                    String sendContent=inputTextArea.getText();
                    byte[] buf=sendContent.getBytes();
                    try{
                        centerTextArea.append("我对"+ipAddress+"::"+remotePort+"说:\n"+inputTextArea.getText()+"\n\n");
                        centerTextArea.setCaretPosition(centerTextArea.getText().length());
                        datagramSocket.send(new DatagramPacket(buf,buf.length,
                                InetAddress.getByName(ipAddress),Integer.parseInt(remotePort)));
                        inputTextArea.setText("");
                    }catch(Exception e1){
                        JOptionPane.showMessageDialog(GuiChat.this,"出错啦，发送不过去");
                        System.out.println(e1.getMessage());
                    }
                }
            });
            clearButton.addActionListener(new ActionListener(){
                public void actionPerformed(ActionEvent e){
                    centerTextArea.setText("");
                }
            });
        }
        public void initSocket(){
            int port=DEFAULT_PORT;
            while(true){
                try{
                    if(datagramSocket!=null&&!datagramSocket.isClosed()){
                        datagramSocket.close();
                    }
                    try{
                        port=Integer.parseInt(JOptionPane.showInputDialog(this,"请输入端口号"
                                ,"端口号",JOptionPane.QUESTION_MESSAGE));
                    }catch (Exception e){
                        JOptionPane.showMessageDialog(null,"你输入的端口号范围得在1——65535之间");
                        continue;
                    }
                    datagramSocket=new DatagramSocket(port);
                    startListen();
                    stateLB.setText("已经在"+port+"端口监听了");
                    break;
                }catch(Exception e){
                    JOptionPane.showMessageDialog(this,"端口被占用了，重新设置端口");
                    stateLB.setText("当前还没有启用端口");
                }
            }
        }
        private void startListen(){
            new Thread(){
                private DatagramPacket p;
                public void run(){
                    byte[] buf=new byte[1024];
                    p=new DatagramPacket(buf,buf.length);
                    while(!datagramSocket.isClosed()){
                        try{
                            datagramSocket.receive(p);
                            centerTextArea.append(p.getAddress().getHostAddress()+"::"+
                                    ((InetSocketAddress)p.getSocketAddress()).getPort()+"对我说:\n"+
                                    new String(p.getData(),0,p.getLength())+"\n\n");
                        }catch(Exception e){
                            e.printStackTrace();
                        }
                    }
                }
            }.start();
        }
        public static void main(String[] args){
            GuiChat Guichat=new GuiChat();
            }
        }