Java动态显示当前日期和时间

package com.xin.test;
 
import java.awt.Color;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.SimpleDateFormat;
import java.util.Date;
 
import javax.swing.JLabel;
import javax.swing.Timer;
import javax.swing.JFrame;
 
public class NowTime extends JFrame {
 
 
 private static final long serialVersionUID = 4306803332677233920L;
 
 // 添加 显示时间的JLabel
 public NowTime() {
 JLabel time = new JLabel();
 time.setForeground(Color.BLUE);
 time.setBounds(30, 0, 900, 130);
 time.setFont(new Font("微软雅黑", Font.BOLD, 80));
 this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 this.setLayout(null);
 this.setTitle("now time");
 this.setBounds(500, 200, 930, 200);
 this.setVisible(true);
 this.add(time);
 this.setTimer(time);
 }
 
 // 设置Timer 1000ms实现一次动作 实际是一个线程
 private void setTimer(JLabel time) {
 final JLabel varTime = time;
 Timer timeAction = new Timer(100, new ActionListener() {
  public void actionPerformed(ActionEvent e) {
  long timemillis = System.currentTimeMillis();
  // 转换日期显示格式
  SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  varTime.setText(df.format(new Date(timemillis)));
  }
 });
 timeAction.start();
 }
 
 // 运行方法
 public static void main(String[] args) {
 new NowTime();
 }
 
}