[JAVA] 날짜 특징에 따른 날짜 구하기

import java.time.DayOfWeek;
import java.time.LocalDateTime;
import java.time.temporal.TemporalAdjusters;

public class DateTimeOperatinExam {

	public static void main(String[] args) {
		LocalDateTime now = LocalDateTime.now();
		System.out.println("현재시간 : " + now.toString());

		// 날짜, 시간의 연산
		LocalDateTime targetDateTime1 = now.plusYears(1).minusMonths(2).plusDays(3).plusHours(4).minusMinutes(5).plusSeconds(6);
		System.out.println("타겟시간 : " + targetDateTime1.toString());

		// 날짜 시간의 직접 변겅
		LocalDateTime targetDateTime2 = now.withYear(2024).withMonth(8).withDayOfMonth(20).withHour(11);
		System.out.println("타겟시간2 : " + targetDateTime2.toString());
		
		// 각 날짜의 특징에 따른 날짜 시간 구해오기
		LocalDateTime targetDateTime3 = now.with(TemporalAdjusters.firstDayOfYear());
		System.out.println("올해의 첫날은? " + targetDateTime3);
		LocalDateTime targetDateTime4 = now.with(TemporalAdjusters.lastDayOfYear());
		System.out.println("올해의 마지막날은? " + targetDateTime4);
		LocalDateTime targetDateTime5 = now.with(TemporalAdjusters.firstDayOfNextYear());
		System.out.println("내년의 첫날은? " + targetDateTime5);
		
		LocalDateTime targetDateTime6 = now.with(TemporalAdjusters.firstDayOfMonth());
		System.out.println("이번달의 첫날은? " + targetDateTime6);
		LocalDateTime targetDateTime7 = now.with(TemporalAdjusters.lastDayOfMonth());
		System.out.println("이번달의 마지막날은? " + targetDateTime7);
		LocalDateTime targetDateTime8 = now.with(TemporalAdjusters.firstDayOfNextMonth());
		System.out.println("다음달의 첫날은? " + targetDateTime8);
		
		LocalDateTime targetDateTime9 = now.with(TemporalAdjusters.firstInMonth(DayOfWeek.MONDAY));
		System.out.println("이번달의 첫 월요일은? " + targetDateTime9);
		LocalDateTime targetDateTime10 = now.with(TemporalAdjusters.next(DayOfWeek.MONDAY));
		System.out.println("현재시간 대비 다음주 월요일의 날짜는? " + targetDateTime10);
		LocalDateTime targetDateTime11 = now.with(TemporalAdjusters.previous(DayOfWeek.MONDAY));
		System.out.println("현재시간 대비 지난주 월요일의 날짜는? " + targetDateTime11);
		
	}

}

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현재시간 : 2022-12-21T17:36:19.032399
타겟시간 : 2023-10-24T21:31:25.032399
타겟시간2 : 2024-08-20T11:36:19.032399
올해의 첫날은? 2022-01-01T17:36:19.032399
올해의 마지막날은? 2022-12-31T17:36:19.032399
내년의 첫날은? 2023-01-01T17:36:19.032399
이번달의 첫날은? 2022-12-01T17:36:19.032399
이번달의 마지막날은? 2022-12-31T17:36:19.032399
다음달의 첫날은? 2023-01-01T17:36:19.032399
이번달의 첫 월요일은? 2022-12-05T17:36:19.032399
현재시간 대비 다음주 월요일의 날짜는? 2022-12-26T17:36:19.032399
현재시간 대비 지난주 월요일의 날짜는? 2022-12-19T17:36:19.032399