用JAVA做个倒计时程序

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.Timer;
import java.util.TimerTask;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;

public class TimeThreadFrame extends JFrame{
// 定义组件
private JLabel lblTime;
private JTextField txtInput;
private JButton btnEnter;
// 构造方法
public TimeThreadFrame(){
// 设置窗体的相关属性
super("TimerThread");
this.setSize(300,200);
this.setLayout(null);
this.setLocation(100,50);
// 创建组件
this.lblTime = new JLabel("请输入倒计时时间");
this.lblTime.setBounds(30,20,200,30);
this.txtInput = new JTextField();
this.txtInput.setBounds(30,70,100,30);
this.btnEnter = new JButton("确定");
this.btnEnter.setBounds(150,70,70,30);
// 给JTextField注册监听
this.txtInput.addKeyListener(new KeyListener(){
public void keyPressed(KeyEvent ke) {
}
public void keyReleased(KeyEvent ke) {
}
public void keyTyped(KeyEvent ke) {
txtInput_KeyTyped(ke);
}
});
// 给JButton注册监听
this.btnEnter.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae){
btnEnter_ActionPerformed(ae);
}
});
// 将各组件添加到窗体上
add(lblTime);
add(txtInput);
add(btnEnter);
// 显示窗体
this.setVisible(true);
}
// 输入时的事件处理，控制用户只能输入数字
public void txtInput_KeyTyped(KeyEvent ke){
if(ke.getKeyChar() < '0' || ke.getKeyChar() > '9'){
ke.setKeyChar('\0');
}
}
// 点击按钮时的事件处理，核心！
public void btnEnter_ActionPerformed(ActionEvent ae){
// 获得用户输入的倒计时时间
String strTime = this.txtInput.getText();
if(strTime.equals("")){
// 检测用户是否输入
this.lblTime.setText("您尚未输入，请输入！");
}
else{
Integer time = Integer.parseInt(strTime);
// 创建线程
TimeThread tt = new TimeThread(this.lblTime,time);
tt.start();
// 创建Timer
Timer timer = new Timer();
timer.schedule(new TimerTask(){
// 启动其他程序
public void run() {
System.out.print("ok");
}
}, time * 1000);

}
}
// 启动窗体
public static void main(String[] args){
new TimeThreadFrame();
}
}
// 时间线程类
class TimeThread extends Thread{
private JLabel lblTime;
private int time;
// 构造方法传入，显示事件的JLabel和倒计时的时间。
public TimeThread(JLabel lblTime, int time){
this.lblTime = lblTime;
this.time = time;
}
// run方法
public void run(){
while(time > 0){
// 显示所剩时间
this.lblTime.setText("所剩时间：" + time);
// 所剩时间减少
time--;
try {
this.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}