（其它）Calendar日期类的使用

 

package com.gc.system;

import java.util.Calendar;

public class CalendarDemo {
	public static void main(String[] args) {
		
		Calendar cal = Calendar.getInstance();
		
		showCurrentDay(cal);
		
		//改变年
		cal.add(Calendar.YEAR, -1);
		
		//改变日
		cal.add(Calendar.DAY_OF_MONTH, 21);
		
		showCurrentDay(cal);
		
	}

	private static void showCurrentDay(Calendar cal) {
		int year = cal.get(Calendar.YEAR);
		int month = cal.get(Calendar.MONTH)+1;//月份需要加1
		int day = cal.get(Calendar.DAY_OF_MONTH);
		System.out.println(year+"年"+month+"月"+day+"日");
	}
}