day18/CalendarDemo2.java

/*
Calendar是一个抽象类


c.set(2020,11,12);			设置日历字段 YEAR、MONTH 和 DAY_OF_MONTH 的值

c.add(Calendar.MONTH,-5);	根据日历的规则，为给定的日历字段添加或减去指定的时间量
*/


import java.util.*;
class CalendarDemo2 
{
	public static void sop(Object obj)
	{
		System.out.println(obj);
	}
	public static void main(String[] args) 
	{
		Calendar c = Calendar.getInstance();//static Calendar getInstance() 使用默认时区和语言环境获得一个日历。
		c.set(2020,11,12);//月是从0-11
		printCalendar(c);

		c.add(Calendar.MONTH,-5);
		printCalendar(c);
	}

	public static void printCalendar(Calendar c)
	{
		//查表，获取月
		String[] mons = {"一月","二月","三月","四月",
						"五月","六月","七月","八月",
						"九月","十月","十一月","十二月"};
		int index=c.get(Calendar.MONTH);
		sop(mons[index]);

		
		//查表，获取星期
		String[] days={"","星期日","星期一","星期二","星期三","星期四","星期五","星期六"};
		int index1 = c.get(Calendar.DAY_OF_WEEK);
		sop(days[index1]);
	}
}