在上一节，我们讨论了Calendar的基本概况，而本节我们将使用java.util包自带的GregorianCalendar——一个真正可以实例化的标准日历类，来建立一个名为JCalendar的GUI日历。如下图：
先把JCalendar的源代码放上来，而分析我们将在下一节进行。各位也可以通过代码中的注释先行了解一下大概的情况。
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.SystemColor;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.Date;
import java.util.StringTokenizer;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JToggleButton;
import javax.swing.SwingConstants;
import javax.swing.UIManager;
/**
* <p>Title: Swing日历</p>
* <p>Description: 操作日期</p>
* @author duxu2004
* @version 1.0.1
*/
public class JCalendar extends JPanel{
//动态表示年月日
private int year=0;
private int month=0;
private int day=0;
//主面板
private JPanel Main = new JPanel();
//日面板
private JPanel jPanelDay = new JPanel();
//月面板
private JPanel jPanelMonth = new JPanel();
//年的输入位置
private JTextField Year = new JTextField();
//月的输入位置
private JTextField Month = new JTextField();
//减少月份
private JButton MonthDown = new JButton();
//增加月份
private JButton MonthUp = new JButton();
private JPanel jPanelButton = new JPanel();
//减少年份
private JButton YearDown = new JButton();
//增加年份
private JButton YearUp = new JButton();
//显示日期的位置
private JLabel Out = new JLabel();
//中国时区，以后可以从这里扩展可以设置时区的功能
private Locale l=Locale.CHINESE;
//主日历
private GregorianCalendar cal=new GregorianCalendar(l);
//星期面板
private JPanel weekPanel=new JPanel();
//天按钮组
private JToggleButton[] days=new JToggleButton[42];
//天面板
private JPanel Days = new JPanel();
//标示
private JLabel jLabel1 = new JLabel();
private JLabel jLabel2 = new JLabel();
private JLabel jLabel3 = new JLabel();
private JLabel jLabel4 = new JLabel();
private JLabel jLabel5 = new JLabel();
private JLabel jLabel6 = new JLabel();
private JLabel jLabel7 = new JLabel();
//当前选择的天数按钮
private JToggleButton cur=null;
//月份天数数组，用来取得当月有多少天
// 1 2 3 4 5 6 7 8 9 10 11 12
private int[] mm={31,28,31,30,31,30,31,31,30,31,30,31};
//空日期构造函数
public JCalendar() {
try {
jbInit();
}
catch(Exception e) {
e.printStackTrace();
