긍정적 사고, 음식의 절제, 규칙적인 운동

String으로 된 날짜에 일자를 더해서 세팅

package com.blue.controller;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;

public class CalendarEx2 { 

       public static void main(String[] arg) { 

             // 2019.12.31 + 2일
            DateFormat dateFormat = new SimpleDateFormat("yyyyMMdd");
             Date date = null;
             try {
                    date = dateFormat.parse("20191231");
             } catch (ParseException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
             }

             Calendar cal = Calendar.getInstance();
             cal.setTime(date);
             cal.add(Calendar.DATE, 2);
             System.out.println(date);
             System.out.println(cal.getTime());
            

             String strDate = dateFormat.format(cal.getTime());
             System.out.println(strDate);
 

       }


}

jsp 현재 날짜, 일주일전 날짜, 한달 전 날짜 구하기.

currentCalendar.add 부분에 -값이 아닌 +값을 대입하면 현재 이후의 날짜를 구할 수 있지요.

 

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page import="java.text.DecimalFormat" %>
<%@ page import="java.text.SimpleDateFormat" %>
<%@ page import="java.util.Calendar" %>

<%
    DecimalFormat df = new DecimalFormat("00");
    Calendar currentCalendar = Calendar.getInstance();

  //현재 날짜 구하기
    String strYear   = Integer.toString(currentCalendar.get(Calendar.YEAR));
    String strMonth  = df.format(currentCalendar.get(Calendar.MONTH) + 1);
    String strDay   = df.format(currentCalendar.get(Calendar.DATE));
    String strDate = strYear + strMonth + strDay;

  //일주일 전 날짜 구하기
    currentCalendar.add(currentCalendar.DATE, -7);
    String strYear7   = Integer.toString(currentCalendar.get(Calendar.YEAR));
    String strMonth7  = df.format(currentCalendar.get(Calendar.MONTH) + 1);
    String strDay7   = df.format(currentCalendar.get(Calendar.DATE));
    String strDate7 = strYear7 + strMonth7 + strDay7;

  //한달 전 날짜 구하기
    currentCalendar.add(currentCalendar.DATE, -24);
    String strYear31   = Integer.toString(currentCalendar.get(Calendar.YEAR));
    String strMonth31  = df.format(currentCalendar.get(Calendar.MONTH) + 1);
    String strDay31   = df.format(currentCalendar.get(Calendar.DATE));
    String strDate31 = strYear31 + strMonth31 + strDay31;
%>

<!-- 현재날짜 -->
<c:set var="nowdate" value='<%=strDate%>' />
<!-- 일주일전 -->
<c:set var="nowdate7" value='<%=strDate7%>' />
<!-- 한달전 -->
<c:set var="nowdate31" value='<%=strDate31%>' />