java date

java.text.DateFormat

java.text.SimpleDateFormat

import java.util.Calendar;
import java.util.Date;

 import java.util.SimpleTimeZone;

    public static Date parseDate(String dateStr) {
        SimpleDateFormat fmt = new SimpleDateFormat("yyyyMMdd");
        SimpleTimeZone timeZone = new SimpleTimeZone(9 * 60 * 60 * 1000, "KST");
        fmt.setTimeZone(timeZone);
        try {
            return fmt.parse(dateStr);
        } catch (ParseException e) {
            return null;
        }
    }

    public static String getDateString(Date date, String format) {
        // 테스트
        if (date == null) {
            return "";
        }
        SimpleDateFormat dateFormat = new SimpleDateFormat(format);
        SimpleTimeZone timeZone = new SimpleTimeZone(9 * 60 * 60 * 1000, "KST");
        dateFormat.setTimeZone(timeZone);
        Calendar cal = dateFormat.getCalendar();
        cal.setTime(date);
        return dateFormat.format(cal.getTime());
    }

    /**
     * 현재 시스템 날짜(yyyyMMdd HH:mm:ss.SSS) 값을 얻어온다.
     * @return ymd
     */
    public static String getTimeSSS() {
        long currentTimes = System.currentTimeMillis();
        return  new SimpleDateFormat("yyyyMMdd HH:mm:ss.SSS").format(new Date(currentTimes));
    }

import java.util.Calendar;
import java.util.GregorianCalendar;

public class WeekdayTest {

    public static void main(String args[]){
        boolean b1 = isMatchedWeekday("20080114", Calendar.MONDAY);
        boolean b2 = isMatchedWeekday("20080105", Calendar.SATURDAY);
        boolean b3 = isMatchedWeekday("20080107", Calendar.MONDAY);

        System.out.println(b1);
        System.out.println(b2);
        System.out.println(b3);
    }

    public static boolean isMatchedWeekday(String date, int weekday){
        int year = Integer.parseInt(date.substring(0,4));
        int month = Integer.parseInt(date.substring(4,6))-1;
        int day = Integer.parseInt(date.substring(6,8));
        Calendar c = new GregorianCalendar();
        c.set(year,month,day);
        return (weekday ==c.get(Calendar.DAY_OF_WEEK));
    }
}

static final String DAY_FORAMT = "yyyy-MM-dd";

static final String TIME_FORAMT = "yyyy-MM-dd HH:mm:ss";

@Test

public void dateTest() throws Exception {

     Date date = DateUtils.parseDate("1850-01-01 00:00:00", new String[]{TIME_FORAMT});

     int count = 200 * 365;

     System.out.println("Expected print out => Actual print out");

     do {

            String actualDateString = DateFormatUtils.format(date, TIME_FORAMT);

            String expectedDateString = DateFormatUtils.format(date, DAY_FORAMT) + " 00:00:00";

            if (!actualDateString.equals(expectedDateString)) {

                   System.out.println(expectedDateString + " => " + actualDateString);

            }

            assertTrue(actualDateString.equals(expectedDateString));

            date = DateUtils.addDays(date,1);

            date = DateUtils.truncate(date, Calendar.DATE);

     } while (count-- > 0);