D-day 계산

package com.hta.lecture.dto;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import com.fasterxml.jackson.annotation.JsonFormat;

import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;


@NoArgsConstructor
@Setter
@Getter
public class UserCouponDto {

	private int userCouponNo;
	private int userNo;
	private int couponNo;
	private int usePeriod;
	private String couponName;
	private int discountRate;
	private int discountPrice;
	private String useStatus;
	private Date useDate;
	private String periodStatus; 
	@JsonFormat(pattern = "yyyy년 M월 d일")	
	private Date pubDate;
	@JsonFormat(pattern = "yyyy년 M월 d일")	
	private Date periodDate;
	
	// 남은 유효기간.
	public long getRemainDate() {
		Date period = this.getPeriodDate(); // 유효기간
		Date now = new Date(); // 현재날짜
		long remainDate; // 남은기간
		
		if(period.getTime() < now.getTime()) {
			remainDate = 0;
		}
		long diffSec = (period.getTime() - now.getTime()) / 1000;
		remainDate = diffSec/(24*60*60);
		return remainDate;
	}
    // remainDate 메서드 실행.
	public static void main(String[] args) throws ParseException {
		UserCouponDto coupon = new UserCouponDto();
		String period = "2022/02/25";
		try {
			Date periodDate = new SimpleDateFormat("yyyy/MM/dd").parse(period);
			coupon.setPeriodDate(periodDate);
		} catch (ParseException e) {
			e.printStackTrace();
		} 
		
		long remainDate = coupon.getRemainDate();
		System.out.println(remainDate);
	}
	
}

getRemainDate 메서드를 실행해 d-day의 날짜를 출력한다.