使用JComboBox关联三个日期选项

showerhan

在做Swing开发时，使用三个JComboBox分别表示年月日，而我们要实现的是当改变年份时，2月的天数可以随之改变。或者月份改变时，这个月的天数随之改变。
 
cb_year = new JComboBox();jp.add(cb_year);cb_month = new JComboBox();jp.add(cb_month);cb_day = new JComboBox();jp.add(cb_day);for(int i = 2011; i>1940; i--)cb_year.addItem(i);for(int i = 1; i<=12; i++)cb_month.addItem(i);for(int i=1; i<=31;i++)cb_day.addItem(i);cb_year.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent evt) { JComboBox cb = (JComboBox) evt.getSource();Object newItem = cb.getSelectedItem();int days =   getDayByYearAndMonth(Integer.parseInt(newItem.toString())              ,Integer.parseInt(cb_month.getSelectedItem().toString()));         cb_day.removeAllItems();for(int i=1; i<=days;i++)cb_day.addItem(i);}});cb_month.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent evt) {JComboBox cb = (JComboBox) evt.getSource();Object newItem = cb.getSelectedItem();int days = getDayByYearAndMonth(                        Integer.parseInt(cb_year.getSelectedItem().toString()),Integer.parseInt(newItem.toString())                );cb_day.removeAllItems();for(int i=1; i<=days;i++)cb_day.addItem(i);}}); 
public static int getDayByYearAndMonth(int year,int month){if(month==2) if((year%4==0&&year%100!=0)||(year%100==0&&year%400==0))return 29;else return 28;else if(month==1 || month==3  || month==5 || month==7 || month==8 || month==10 || month==12)return 31;else return 30;}  
 
 我对这些不熟，就算是抛砖引玉吧~~