[JAVA] 11. 자바 Utils & Lib Ⅰ. JRE 라이브러리 import (2) LocalDate

날짜 관련 메서드들

1. 현재 날짜

        LocalDate nowDate = LocalDate.now();
        System.out.println(nowDate);

2. 현재 시간

        LocalDateTime nowDateTime = LocalDateTime.now();
        System.out.println(nowDateTime);

3. 날짜 더하기/빼기

        LocalDate plusDays = nowDate.plusDays(-10000);
        LocalDate plusDays2 = nowDate.plusDays(-20);
        System.out.println(plusDays);
        System.out.println(plusDays2);

4. 주 더하기/빼기

        LocalDate plusWeeks = nowDate.plusWeeks(2);
        LocalDate plusWeeks2 = nowDate.plusWeeks(-2);
        System.out.println(plusWeeks);

5. 월 더하기/빼기

        LocalDate plusMonths = nowDate.plusMonths(2);
        System.out.println(plusMonths);

6. 현재날짜의 연도, 월, 요일 확인하기

        System.out.println(nowDate.getYear());
        System.out.println(nowDate.getMonth());
        System.out.println(nowDate.getDayOfMonth());

package ex08;

import java.time.LocalDate;
import java.time.LocalDateTime;

public class LDate01 {
    public static void main(String[] args) {
        // 1. 현재 날짜
        LocalDate nowDate = LocalDate.now();
        System.out.println(nowDate);

        // 2. 현재 시간
        LocalDateTime nowDateTime = LocalDateTime.now();
        System.out.println(nowDateTime);

        // 3. 날짜 더하기/빼기
        LocalDate plusDays = nowDate.plusDays(-10000);
        LocalDate plusDays2 = nowDate.plusDays(-20);
        System.out.println(plusDays);
        System.out.println(plusDays2);

        // 4. 주 더하기/빼기
        LocalDate plusWeeks = nowDate.plusWeeks(2);
        LocalDate plusWeeks2 = nowDate.plusWeeks(-2);
        System.out.println(plusWeeks);
        // 5. 월 더하기/빼기
        LocalDate plusMonths = nowDate.plusMonths(2);
        System.out.println(plusMonths);

        // 6. 현재날짜의 연도, 월, 요일 확인하기
        System.out.println(nowDate.getYear());
        System.out.println(nowDate.getMonth());
        System.out.println(nowDate.getDayOfMonth());
    }
}

날짜 비교 메서드들

ChronoUnit 클래스

package ex08;

import java.time.LocalDateTime;
import java.time.temporal.ChronoUnit;

public class Chrono01 {
    public static void main(String[] args) {
        LocalDateTime writeTime = LocalDateTime.of(2025, 02, 11, 10, 3); // 직접 날짜 생성
        LocalDateTime nowTime = LocalDateTime.now();

        long daysBetween = ChronoUnit.DAYS.between(writeTime, nowTime); // 큰 숫자가 뒤
        long minsBetween = ChronoUnit.MINUTES.between(writeTime, nowTime);

        System.out.println(daysBetween + "일전");
        System.out.println(minsBetween + "분전");
    }
}