Question

帮忙解释一个Java小程序（秒表）

我是一名Java新手，在网上找了一个秒表小程序，哪位大哥帮忙解释下这些代码的意思。添加些注释  谢谢了package com.sofmit.tool;import javax.swing.*;import java.awt.event.ActionListener;import java.awt.event.ActionEvent;import java.awt.*;import java.util.Date;import java.text.SimpleDateFormat;public class StopWatch extends JFrame { JButton btnStart, btnStop;  JLabel label; Timer timer; public StopWatch() {  label = new JLabel("00:00:00.000");  btnStart = new JButton("start");  btnStop = new JButton("stop");  final int delay = 100;  final Date startTime = new Date();  final SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss.S");  final Action taskPerformer = new AbstractAction() {   public void actionPerformed(ActionEvent evt) {    //显示时间       Date d = new Date(System.currentTimeMillis()      - startTime.getTime() - 28800000);    label.setText(sdf.format(d));    label.repaint();   }  };  btnStart.addActionListener(new ActionListener() {   public void actionPerformed(ActionEvent evt) {    startTime.setTime(new Date().getTime());    timer = new Timer(delay, taskPerformer);    timer.start();   }  });  btnStop.addActionListener(new ActionListener() {   public void actionPerformed(ActionEvent evt) {    if (timer != null && timer.isRunning())     timer.stop();   }  });  Container c = getContentPane();  c.add(label, BorderLayout.NORTH);  c.add(btnStart, BorderLayout.CENTER);  c.add(btnStop, BorderLayout.SOUTH); } public static void main(String[] args) {  javax.swing.SwingUtilities.invokeLater(new Runnable() {   public void run() {    createAndShowGUI();   }  }); } private static void createAndShowGUI() {  StopWatch window = new StopWatch();  window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  window.pack();  window.setVisible(true); }}

Answer 1

package com.sofmit.tool;
import javax.swing.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.*;import java.util.Date;
import java.text.SimpleDateFormat;
public class StopWatch extends JFrame {
JButton btnStart, btnStop;
JLabel label; Timer timer;
public StopWatch() {
label = new JLabel("00:00:00.000");
btnStart = new JButton("start");
btnStop = new JButton("stop");
final int delay = 100;
final Date startTime = new Date();
final SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss.S");
final Action taskPerformer = new AbstractAction() {
public void actionPerformed(ActionEvent evt)
{ //显示时间
Date d = new Date(System.currentTimeMillis() - startTime.getTime() - 28800000); label.setText(sdf.format(d)); label.repaint();
}
};
btnStart.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent evt) {
startTime.setTime(new Date().getTime());
timer = new Timer(delay, taskPerformer); timer.start(); } });
btnStop.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (timer != null && timer.isRunning())
timer.stop();
} });
Container c = getContentPane();
c.add(label, BorderLayout.NORTH);
c.add(btnStart, BorderLayout.CENTER);
c.add(btnStop, BorderLayout.SOUTH); }
public static void main(String[] args)
{
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() { createAndShowGUI(); } }); }
private static void createAndShowGUI() { StopWatch window = new StopWatch(); window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); window.pack(); window.setVisible(true); }}

你下载个java文档，中文版的，或者先看看孙鑫的java无难事，这是给你最好的思路！

Answer 2

package test;
import javax.swing.*;
import java.awt.event.
ActionListener;
import java.awt.event.ActionEvent;
import java.awt.*;
import java.util.Date;
import java.text.SimpleDateFormat;
/** 导包 **/
public class test1 extends JFrame {
JButton btnStart, btnStop;
JLabel label;
Timer timer;
public test1() {
label = new JLabel("00:00:00.000"); //初始化一个标签显示00:00:00.000也就是秒表在没有开始的时候显示
btnStart = new JButton("start"); //开始按钮
btnStop = new JButton("stop"); //停止按钮
final int delay = 1000;
final Date startTime = new Date(); //得到当前日期
final SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss.S"); //日期格式
final Action taskPerformer = new AbstractAction() {
public void actionPerformed(ActionEvent evt) { //显示时间

Date d = new Date(System.currentTimeMillis() - startTime.getTime() - 28800000); //要显示的日期运算
label.setText(sdf.format(d)); label.repaint(); } }; //给标签赋值
btnStart.addActionListener(new ActionListener() { //按钮定义方法
public void actionPerformed(ActionEvent evt) {
startTime.setTime(new Date().getTime());
timer = new Timer(delay, taskPerformer);//在delay/1000秒后执行taskPerformer任务

timer.start(); //开始timer
}
});
btnStop.addActionListener(new ActionListener() { //按钮定义方法
public void actionPerformed(ActionEvent evt) {
if (timer != null && timer.isRunning())
timer.stop(); //停止timer
}
});
Container c = getContentPane(); //得到窗口中的顶级容器
c.add(label, BorderLayout.NORTH); //
c.add(btnStart, BorderLayout.CENTER); //
c.add(btnStop, BorderLayout.SOUTH);
}
public static void main(String[] args) {
//启动程序
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {createAndShowGUI();}
});
}
private static void createAndShowGUI() {
test1 window = new test1();
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//使用 System exit 方法退出应用程序。仅在应用程序中使用。
window.pack(); //验证这个视窗的所有子元件
window.setVisible(true); //窗口显示
}
}