利用GregorianCalendar物件內部的get方法 getFirstDayweek方法獲得當地星期的起始日。 我們不必知道GregorianCalendar類如何計算星期數與天數。掌握set與get，add方法。

在這裡插入程式碼片
```package Qingdenggufuo;

import java.text.DateFormatSymbols;
import java.util.Calendar;
import java.util.GregorianCalendar;

import javax.imageio.metadata.IIOInvalidTreeException;

public class Date1 {
	public static void main(String[] args){
  GregorianCalendar d=new GregorianCalendar();//構造d為當前日期
  int today =d.get(Calendar.DAY_OF_MONTH);
  int month =d.get(Calendar.MONTH);
  d.set(Calendar.DAY_OF_MONTH,1);//設定d為月開始日期
   int weekday=d.get(Calendar.DAY_OF_WEEK);//得到d為該星期的第幾天
   int firstDayOfWeek =d.getFirstDayOfWeek();//獲得當前星期的起始日
   int indent=0;
   while(weekday!= firstDayOfWeek){
	indent++;
	d.add(Calendar.DAY_OF_MONTH,-1);
	weekday=d.get(Calendar.DAY_OF_WEEK);
}
   String[] weekdayNames =new DateFormatSymbols().getShortWeekdays();
   do{
	   System.out.printf("%4s",weekdayNames[weekday]);
	   d.add(Calendar.DAY_OF_MONTH, 1);
	   weekday=d.get(Calendar.DAY_OF_WEEK);
	   }
   while(weekday!=firstDayOfWeek);
   
	   System.out.println();
	   for(int i=1;i<=indent;i++)
		System.out.println(" ");
	   d.set(Calendar.DAY_OF_MONTH, 1);
	   do{
		   int day=d.get(Calendar.DAY_OF_MONTH);
		   System.out.printf("%3d",day);
		   if(day==today)
			System.out.print("*");   
		   else 
			   System.out.print(" ");
		   d.add(Calendar.DAY_OF_MONTH, 1);
		   weekday =d.get(Calendar.DAY_OF_WEEK);
		   if(weekday==firstDayOfWeek)
			   System.out.println();			  
	   }   
	   while (d.get(Calendar.MONTH)==month);
	   if(weekday!=firstDayOfWeek)
		   System.out.println(); 
	}	
}





 

``