高分求解决方案,为什么我JComboBox选择了却没效果
这是个日历程序,我想通过选择月份改变每月的日历.为什么选择却没有效果呢? 
 package   Calendar;   
 import   java.awt.*; 
 import   java.awt.event.*; 
 import   javax.swing.*; 
 import   java.util.*;   
 class   Calendarday   extends   JPanel   {   
 	private   JPanel   dayPanel;   
 	private   static   int   count   =   0;   
 	private   JLabel[]   label;   
 	private   static   final   GregorianCalendar   d   =   new   GregorianCalendar(); 
 	private   static   final   GregorianCalendar   day   =   new   GregorianCalendar();   
 	public   void   setMonth(int   month){ 
 		d.set(Calendar.MONTH,   month-1); 
 		day.set(Calendar.MONTH,   month-1); 
 		System.out.println(d.get(Calendar.MONTH)); 
 	}  	 
 	public   void   setYear(int   year){ 
 		d.set(Calendar.YEAR,   year); 
 		day.set(Calendar.YEAR,   year); 
 	} 
 	public   Calendarday()   { 
 		//   日期容器开始:   
 		day.set(Calendar.DAY_OF_MONTH,   1); 
 		int   weekday   =   day.get(Calendar.DAY_OF_WEEK);  		 
 		dayPanel   =   new   JPanel(); 
 		//   根据每月的第一天来判断,决定日期表格容器的大小: 
 		if   (weekday   ==   7   ||   weekday==6)   { 
 			dayPanel.setLayout(new   GridLayout(6,   7)); 
 			label   =   new   JLabel[42]; 
 			for   (int   i   =   0;   i    <   label.length;   i++)   { 
 				label[i]   =   new   JLabel( "          "); 
 				dayPanel.add(label[i]); 
 			} 
 		}   else   { 
 			dayPanel.setLayout(new   GridLayout(5,   7)); 
 			label   =   new   JLabel[35]; 
 			for   (int   i   =   0;   i    <   label.length;   i++)   { 
 				label[i]   =   new   JLabel( "          "); 
 				dayPanel.add(label[i]); 
 				label[i].addMouseListener(new   mousel()); 
 			}  			 
 		} 
 		//   日期表格容器结束;   
 		printcalendar(); 
 	}     
 	//   输出日期表 
 	public   void   printcalendar()   { 
 		int   today   =   d.get(Calendar.DAY_OF_MONTH); 
 		int   month   =   d.get(Calendar.MONTH);  		   
 		d.set(Calendar.DAY_OF_MONTH,   1); 
 		int   weekday   =   d.get(Calendar.DAY_OF_WEEK);  		 
 		for   (int   i   =   Calendar.SUNDAY;   i    <   weekday;   i++)   { 
 			label[count].setText( "          "); 
 			count++; 
 		} 
 		System.out.println(month+ "ss "); 
 		do   { 
 			int   day   =   d.get(Calendar.DAY_OF_MONTH); 
 			label[count].setText(Integer.toString(day)); 
 			if   (day   ==   today)   { 
 				label[count].setText(label[count].getText()   +    "* "); 
 			}   else   { 
 				label[count].setText(label[count].getText()   +    "       "); 
 			}  			 
 			d.add(Calendar.DAY_OF_MONTH,   1); 
 			weekday   =   d.get(Calendar.DAY_OF_WEEK); 
 			count++; 
 		}   while   (d.get(Calendar.MONTH)   ==   month); 
 		count=0; 
 	}  	 
 	private   class   mousel   extends   MouseAdapter{  		 
 		public   void   mousePressed(MouseEvent   event){}					 
 		public   void   mouseClicked(MouseEvent   event){}