java 11일차 _ 01. 유틸리티 클래스( 날짜 데이터 Calender )

나. java.util.Calender
- Data 보다 나중에 지원
- new 방법으로 생성하지 않고 메서드를 이용해서 인스턴스를 얻는다.
ex)  
Calendar cal = Calendar.getInstance( );
// getInstance( ) 안에서 new 하고 리턴해줌

int year = cal.get(Calendar.YEAR); // 년도 얻기

 

package exam19_Util;

import java.util.Calendar;

public class Util04_날짜2_Calendar {
	
	public static void main(String[] args) {
		
		Calendar cal = Calendar.getInstance();
//		System.out.println(cal);
				
		/*
		 * >>>
		 * 
		 * java.util.GregorianCalendar[time=1711086466317,areFieldsSet=true,
		 * areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.
		 * ZoneInfo[id="Asia/Seoul",
		 * 				offset=32400000,
		 * 				dstSavings=0,
		 * 				useDaylight=false,
		 * 				transitions=30,
		 * 				lastRule=null],
		 * 				firstDayOfWeek=1,
		 * 				minimalDaysInFirstWeek=1,
		 * 				ERA=1,
		 * 				YEAR=2024,
		 * 				MONTH=2, // 월은 내부적으로 배열로 관리 ( 0: 1월, 1: 2월, 2: 3월 ,... )
		 * 				WEEK_OF_YEAR=12,
		 * 				WEEK_OF_MONTH=4,
		 * 				DAY_OF_MONTH=22,
		 * 				DAY_OF_YEAR=82,
		 * 				DAY_OF_WEEK=6,
		 * 				DAY_OF_WEEK_IN_MONTH=4,
		 * 				AM_PM=1,
		 * 				HOUR=2,
		 * 				HOUR_OF_DAY=14,
		 * 				MINUTE=47,
		 * 				SECOND=46,
		 * 				MILLISECOND=317,
		 * 				ZONE_OFFSET=32400000,
		 * 				DST_OFFSET=0]
		 */
		
		// 현재시간 얻기
		int year = cal.get(Calendar.YEAR);
		int month = cal.get(Calendar.MONTH)+1; // 0 부터 관리
		int day = cal.get(Calendar.DAY_OF_MONTH);
		int hour = cal.get(Calendar.HOUR_OF_DAY);
		int minute = cal.get(Calendar.MINUTE);
		int second = cal.get(Calendar.SECOND);
		
		System.out.println("년도: " + year);
		System.out.println("월: " + month);
		System.out.println("일: " + day);
		System.out.println("시간: " + hour);
		System.out.println("분: " + minute);
		System.out.println("초: " + second);
		System.out.println();
		
		// 특정 날짜 설정
		Calendar cal2 = Calendar.getInstance();
		cal2.set(2002, 2, 15);
		
		int year2 = cal2.get(Calendar.YEAR);
		int month2 = cal2.get(Calendar.MONTH)+1; // 0 부터 관리
		int day2 = cal2.get(Calendar.DAY_OF_MONTH);
		System.out.println("설정 년도: " + year2);
		System.out.println("설정 월: " + month2);
		System.out.println("설정 일: " + day2);
	}
}