伝統的な方法
@Test
public void testDateRound() throws ParseException {
Date date = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS").parse("2016-04-21T10:28:18.109Z");
System.out.println(date);
Calendar cl = Calendar.getInstance();
cl.setTime(date);
cl.set(Calendar.HOUR_OF_DAY, 23);
cl.set(Calendar.MINUTE, 59);
cl.set(Calendar.SECOND, 59);
cl.set(Calendar.MILLISECOND, 999);
System.out.println(cl.getTime());
cl.add(Calendar.MILLISECOND, 1);
System.out.println(cl.getTime());
}
出力
Thu Apr 21 10:28:18 GMT+03:00 2016
Thu Apr 21 23:59:59 GMT+03:00 2016
Fri Apr 22 00:00:00 GMT+03:00 2016