문자열 날짜 포멧 변경

 

문자열 날짜를 포멧형식을 변경해서 사용할 일이 있어서 간단하게 만들어 보았다, 어려운건 아니라서 나름의 형식에 따라 필요한 부분만 추가해 보았다.

 

날짜 관련 유틸

...
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
...


public class DateUtils {
  ...
  
  /**
   * DateUtils.formatLocalDateString("20230405", "yyyyMMdd", "yy.MM.dd");
   *
   * @param date
   * @param fromPattern
   * @param toPattern
   * @return
   */
  public static String formatLocalDateString(String date, String fromPattern, String toPattern) {
    LocalDate localDate = LocalDate.parse(date, DateTimeFormatter.ofPattern(fromPattern));
    return localDate.format(DateTimeFormatter.ofPattern(toPattern));
  }

  /**
   * DateUtils.formatLocalDateTimeString("2023-04-05 13:01:40.0", "yyyy-MM-dd HH:mm:SS", "yy.MM.dd HH:mm");
   *
   * @param date
   * @param fromPattern
   * @param toPattern
   * @return
   */
  public static String formatLocalDateTimeString(String date, String fromPattern, String toPattern) {
    LocalDateTime localDate = LocalDateTime.parse(date, DateTimeFormatter.ofPattern(fromPattern));
    return localDate.format(DateTimeFormatter.ofPattern(toPattern));
  }
  
  /**
   * DateUtils.formatDate(DateUtils.now(), "HH:mm:ss")
   *
   * @param date
   * @param format
   * @return
   */
  public static String formatDate(Date date, String format) {
    SimpleDateFormat dateFormat = new SimpleDateFormat(format);
    return dateFormat.format(date);
  }

  /**
   * DateUtils.now()
   *
   * @return
   */
  public static Date now() {
    return new Date();
  }
  
  
  
  
  /**
   * DateUtil.getNow("yyyyMMddHHmmss")
   *
   * @return
   */
  public static String getNow(String format) {
    return getDate(new Date(), format);
  }

  public static String getDate(String format) {
    return getDate(new Date(), format);
  }
  
  /**
   * DateUtils.getDate("yyyyMMdd")
   *
   * @return
   */
  public static String getDate(Date date, String format) {
    Locale currentLocale = new Locale("KOREAN", "KOREA");
    SimpleDateFormat formatter = new SimpleDateFormat(format, currentLocale);
    return formatter.format(date);
  }
  
  
  /**
   * <p>데이트 포맷과 데이트 문자열을 입력받아 Date 객체를 반환함.
   *
   * @param format
   * @param date
   * @return
   * @throws ParseException <p><pre>
   *                         - 사용 예
   *                         Date date = DateUtil.getDateFromStringFormat("yyyy-MM-dd", "2015-06-15")
   *                        </pre>
   */
  public static Date getDateFromStringFormat(String format, String date) throws ParseException {
    SimpleDateFormat f = new SimpleDateFormat(format);
    return f.parse(date);
  }
  
  /**
   * DateUtils.addMonths(DateUtils.getDateFromStringFormat("yyyyMMdd", "20230130"), 1)
   *
   * @param date
   * @param monthsToAdd
   * @return
   */
  public static Date addMonths(Date date, int monthsToAdd) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.add(Calendar.MONTH, monthsToAdd);

    return cal.getTime();
  }
  
  
  ...
}

 

테스트 케이스

import junit.framework.TestCase;
import org.junit.Test;

public class DateUtilsTest extends TestCase {
    ...
    
    @Test
    public void testFormatLocalDateString() {
        String result = DateUtils.formatLocalDateString("20230405", "yyyyMMdd", "yyyy-MM-dd");
        assertEquals(result, "2023-04-05");
    }

    @Test
    public void testFormatLocalDateTimeString() {
        String result = DateUtils.formatLocalDateTimeString("2023-04-05 13:01:40.0", "yyyy-MM-dd HH:mm:ss.S", "yy.MM.dd HH:mm");
        assertEquals(result, "23.04.05 13:01");
    }
    
    @Test
    public void testFormatDate() {
        String result = DateUtils.formatDate(DateUtils.now(), "HH:mm:ss");
//        System.out.println("result : " + result);
    }

    @Test
    public void testAddMonth() throws ParseException {
        Date now = DateUtils.getDateFromStringFormat("yyyyMMdd", "20230130");
        Date date = DateUtils.addMonths(now, 1);

        String result = DateUtils.getDate(date, "yyyyMMdd");

        assertEquals(result, "20230228");
    }
}

 

후다닥.