MyCalendar类：

得到用于显示日期数组a[ ]

import java.util.Calendar;

public class MyCalendar {
String day[];
int year = 2020,month=0;

public String[] getDay() {
return day;
}
public void setDay(String[] day) {
this.day = day;
}
public int getYear() {
return year;
}
public void setYear(int year) {
this.year = year;
}
public int getMonth() {
return month;
}
public void setMonth(int month) {
this.month = month;
}
private boolean isLeapYear() {
if(this.year%4==0 && this.year%100!=0){
return true;
}else 
if(this.year%400==0){
return true;
}else

return false;
}


//获得显示数组
public String[] getCalendar(){
Calendar calendar=Calendar.getInstance();
String a[]=new String[42];
calendar.set(year,month-1,1);
int weekday=calendar.get(Calendar.DAY_OF_WEEK)-1;
int day=0;
int days = 31;
if (this.month == 4 || this.month == 6 || this.month == 9 || this.month == 11)
days = 30;
if (this.month == 2 && isLeapYear())
days = 29;
if (this.month == 2 && !isLeapYear())
days = 28;

for(int i = weekday,n=1;i< weekday +days;i++){
a[i]=String.valueOf(n);
n++;
}
return a;
}

}

MyFrame类：

创造显示面板，主要用到JTable。

public class MyFrame extends JFrame implements ActionListener {
//存储数据
MyCalendar calendar = new MyCalendar();
JComboBox choiceYear,choiceMonth;
JTable table = null;
JPanel root = new JPanel();
JLabel lyear, lmonth;

private Object[] name = {"日","一","二","三","四","五","六"};
private TableModel tableModel = new DefaultTableModel(name,6);

//  private static int row = 6;
//  private static int column = 7;

public MyFrame(String title) {
super(title);


this.setContentPane(root);
root.setLayout(new BorderLayout());
//年月选择栏
choiceYear=new JComboBox();
choiceMonth=new JComboBox();
lyear=new JLabel("年");
lmonth=new JLabel("月 ");
for(int i=1990;i<2050;i++)
choiceYear.addItem(i);
choiceYear.addActionListener(this);
for(int i=1;i<=12;i++)
choiceMonth.addItem(i);
choiceMonth.addActionListener(this);

JPanel pNorth=new JPanel();

pNorth.add(choiceYear);
pNorth.add(lyear);
pNorth.add(choiceMonth);
pNorth.add(lmonth);
root.add(pNorth,BorderLayout.NORTH);

// 表格初始化
setYearAndMonth( 1990, 1);



}

//设置年月日
public void setYearAndMonth(int y,int m){
calendar.setYear(y);
calendar.setMonth(m);
String day[]=calendar.getCalendar();
Vector