java进阶_Calendar类

Calendar类

代码演示

package com.tian.date;

import java.util.Calendar;

public class Test {
	public static void main(String[] args) {
		//获取对象
		Calendar c=Calendar.getInstance();
		System.out.println(c);
		/*
		 * java.util.GregorianCalendar
		 * [time=1625475251088,areFieldsSet=true,areAllFieldsSet=true,
		 * lenient=true,zone=sun.util.calendar.ZoneInfo
		 * [id="Asia/Shanghai",offset=28800000,dstSavings=0,
		 * useDaylight=false,transitions=31,lastRule=null],
		 * firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,
		 * YEAR=2021,MONTH=6,WEEK_OF_YEAR=28,WEEK_OF_MONTH=2,DAY_OF_MONTH=5,
		 * DAY_OF_YEAR=186,DAY_OF_WEEK=2,DAY_OF_WEEK_IN_MONTH=1,
		 * AM_PM=1,HOUR=4,HOUR_OF_DAY=16,MINUTE=54,SECOND=11,MILLISECOND=88,
		 * ZONE_OFFSET=28800000,DST_OFFSET=0]
		 */
		int year=c.get(Calendar.YEAR);
		int month=c.get(Calendar.MONTH)+1;
		int date=c.get(Calendar.DATE);
		System.out.println(year+"年"+month+"月"+date+"日");//2021年7月5日
	}
}

Calendar常用方法

代码演示

package com.tian.date;

import java.util.Calendar;

public class Test1 {
	public static void main(String[] args) {
		Calendar c = Calendar.getInstance();
		//get方法
//		int year=c.get(Calendar.YEAR);
//		int month=c.get(Calendar.MONTH)+1;
//		int date=c.get(Calendar.DATE);
//		System.out.println(year+"年"+month+"月"+date+"日"); 
//2021年7月5日

		//add方法
/*		c.add(Calendar.YEAR, -3);
		int year = c.get(Calendar.YEAR);
		int month = c.get(Calendar.MONTH) + 1;
		int date = c.get(Calendar.DATE);
		System.out.println(year + "年" + month + "月" + date + "日"); // 2018年7月5日
*/	
		//10年后的5天前
/*		c.add(Calendar.YEAR, 10);
		c.add(Calendar.DATE, -5);
		int year = c.get(Calendar.YEAR);
		int month = c.get(Calendar.MONTH) + 1;
		int date = c.get(Calendar.DATE);
		System.out.println(year + "年" + month + "月" + date + "日");//2031年6月30日
	*/
	
		//set方法
		c.set( 2048,11,11);
		int year = c.get(Calendar.YEAR);
		int month = c.get(Calendar.MONTH) + 1;
		int date = c.get(Calendar.DATE);
		System.out.println(year + "年" + month + "月" + date + "日");//2048年12月11日
		
	}
}

案例 二月天

• 需求：获取任意一年的二月有多少天

package com.tian.date;

import java.util.Calendar;
import java.util.Scanner;

public class Test {
	public static void main(String[] args) {
		// 键盘录入任意的年份
		Scanner sc = new Scanner(System.in);
		System.out.println("请输入年份:");
		int year = sc.nextInt();
		//设置日历对象的年月日
		Calendar c = Calendar.getInstance();
		c.set(year, 2, 1);
		//System.out.println(c.get(Calendar.YEAR) +"年"+ (c.get(Calendar.MONTH)+1)+"月"+c.get(Calendar.DATE)+"日");
		
		//3月1日往前推一天，就是2月的最后一天
		c.add(Calendar.DATE, -1);
		//获取这一天输出即可
		int date = c.get(Calendar.DATE);
		System.out.println(year + "年的2月份有" + date + "天");
	}
}