创建一个小窗口 实现最简单信息交互

 

import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Color;
import java.awt.Font;
import java.awt.Frame;
import java.awt.Panel;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.BufferedWriter;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class Demo4_GUIChat extends Frame {

 private TextField tf;
 private Button send;
 private Button log;
 private Button clear;
 private Button shake;
 private TextArea viewText;
 private TextArea sendText;
 private DatagramSocket socket;
 private BufferedWriter bw;
 /**
  * @param args
  * GUI聊天
  */
 public Demo4_GUIChat() {
  init();
  southPanel();
  centerPanel();
  event();
 }

 public void event() {
  this.addWindowListener(new WindowAdapter() {
   @Override
   public void windowClosing(WindowEvent e) {
    try {
     socket.close();
     bw.close();
    } catch (IOException e1) {
     
     e1.printStackTrace();
    }
    System.exit(0);
   }
  });
  
  send.addActionListener(new ActionListener() {
   
   @Override
   public void actionPerformed(ActionEvent e) {
    try {
     send();
    } catch (IOException e1) {
     
     e1.printStackTrace();
    }
   }

  });
  
  log.addActionListener(new ActionListener() {
   
   @Override
   public void actionPerformed(ActionEvent e) {
    try {
     logFile();
    } catch (IOException e1) {
     
     e1.printStackTrace();
    }
   }

  });
  
  clear.addActionListener(new ActionListener() {
   
   @Override
   public void actionPerformed(ActionEvent e) {
    viewText.setText("");
   }
  });
  
  shake.addActionListener(new ActionListener() {
   
   @Override
   public void actionPerformed(ActionEvent e) {
    try {
     send(new byte[]{-1},tf.getText());
    } catch (IOException e1) {
     
     e1.printStackTrace();
    }
   }

  });
  
  sendText.addKeyListener(new KeyAdapter() {
   @Override
   public void keyReleased(KeyEvent e) {
    //if(e.getKeyCode() == KeyEvent.VK_ENTER && e.isControlDown()) { //isControlDown ctrl是否被按下
    if(e.getKeyCode() == KeyEvent.VK_ENTER) {
     try {
      send();
     } catch (IOException e1) {
      
      e1.printStackTrace();
     }
    }
   }
  });
 }
 

 private void shake() {
  int x = this.getLocation().x;       //获取横坐标位置
  int y = this.getLocation().y;       //获取纵坐标位置
  
  for(int i = 0; i < 20; i++) {
   try {
    this.setLocation(x + 20, y + 20);
    Thread.sleep(20);
    this.setLocation(x + 20, y - 20);
    Thread.sleep(20);
    this.setLocation(x - 20, y + 20);
    Thread.sleep(20);
    this.setLocation(x - 20, y - 20);
    Thread.sleep(20);
    this.setLocation(x, y);
   } catch (InterruptedException e) {
    
    e.printStackTrace();
   }
  }
 }
 
 private void logFile() throws IOException {
  bw.flush();         //刷新缓冲区
  FileInputStream fis = new FileInputStream("config.txt");
  ByteArrayOutputStream baos = new ByteArrayOutputStream(); //在内存中创建缓冲区
  
  int len;
  byte[] arr = new byte[8192];
  while((len = fis.read(arr)) != -1) {
   baos.write(arr, 0, len);
  }
  
  String str = baos.toString();    //将内存中的内容转换成了字符串
  viewText.setText(str);
  
  fis.close();
 }
 
 private void send(byte[] arr, String ip) throws IOException {
  DatagramPacket packet =
    new DatagramPacket(arr, arr.length, InetAddress.getByName(ip), 9999);
  socket.send(packet);      //发送数据
 }
 
 private void send() throws IOException {
  String message = sendText.getText();  //获取发送区域的内容
  String ip = tf.getText();     //获取ip地址;
  ip = ip.trim().length() == 0 ? "255.255.255.255" : ip;
  
  send(message.getBytes(),ip);
  
  String time = getCurrentTime();    //获取当前时间
  String str = time + " 我对:" + (ip.equals("255.255.255.255") ? "所有人" : ip) + "说 " + message + " "; //alt + shift + l 抽取局部变量
  viewText.append(str);      //将信息添加到显示区域中
  bw.write(str);        //将信息写到数据库中
  sendText.setText("");
  
  
 }
 
 private String getCurrentTime() {
  Date d = new Date();      //创建当前日期对象
  SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");
  return sdf.format(d);      //将时间格式化
 }

 public void centerPanel() {
  Panel center = new Panel();     //创建中间的Panel
  viewText = new TextArea();
  sendText = new TextArea(5,1);
  center.setLayout(new BorderLayout());  //设置为边界布局管理器
  center.add(sendText,BorderLayout.SOUTH); //发送的文本区域放在南边
  center.add(viewText,BorderLayout.CENTER); //显示区域放在中间
  viewText.setEditable(false);    //设置不可以编辑
  viewText.setBackground(Color.WHITE);  //设置背景颜色
  sendText.setFont(new Font("xxx", Font.PLAIN, 15));
  viewText.setFont(new Font("xxx", Font.PLAIN, 15));
  this.add(center,BorderLayout.CENTER);
 }

 public void southPanel() {
  Panel south = new Panel();     //创建南边的Panel
  tf = new TextField(15);
  tf.setText("127.0.0.1");
  send = new Button("发 送");
  log = new Button("记 录");
  clear = new Button("清 屏");
  shake = new Button("震 动");
  south.add(tf);
  south.add(send);
  south.add(log);
  south.add(clear);
  south.add(shake);
  this.add(south,BorderLayout.SOUTH);   //将Panel放在Frame的南边
 }

 public void init() {
  this.setLocation(500, 50);
  this.setSize(400, 600);
  new Receive().start();
  try {
   socket = new DatagramSocket();
   bw = new BufferedWriter(new FileWriter("config.txt",true)); //需要在尾部追加
  } catch (Exception e) {
   
   e.printStackTrace();
  }
  this.setVisible(true);
 }
 private class Receive extends Thread {   //接收和发送需要同时执行,所以定义成多线程的
  public void run() {
   try {
    DatagramSocket socket = new DatagramSocket(9999);
    DatagramPacket packet = new DatagramPacket(new byte[8192], 8192);
    
    while(true) {
     socket.receive(packet);    //接收信息
     byte[] arr = packet.getData();  //获取字节数据
     int len = packet.getLength();  //获取有效的字节数据
     if(arr[0] == -1 && len == 1) {  //如果发过来的数组第一个存储的值是-1,并且数组长度是1
      shake();      //调用震动方法
      continue;      //终止本次循环,继续下次循环,因为震动后不需要执行下面的代码
     }
     String message = new String(arr,0,len); //转换成字符串
     
     String time = getCurrentTime();  //获取当前时间
     String ip = packet.getAddress().getHostAddress(); //获取ip地址
     String str = time + " " + ip + " 对我说: " + message + " ";
     viewText.append(str);
     bw.write(str);
    }
   } catch (Exception e) {
    
    e.printStackTrace();
   }
  }
 }
 
 public static void main(String[] args) {
  new Demo4_GUIChat();
 }

}