public long endTimeToTimestamp(Step step, String dateStr) {
        switch (step) {
            case DAY:
                return YYYY_MM_DD.parseDateTime(dateStr).plusDays(1).getMillis();
            case HOUR:
                return YYYY_MM_DD_HH.parseDateTime(dateStr).plusHours(1).getMillis();
            case MINUTE:
                return YYYY_MM_DD_HHMM.parseDateTime(dateStr).plusMinutes(1).getMillis();
            case SECOND:
                return YYYY_MM_DD_HHMMSS.parseDateTime(dateStr).plusSeconds(1).getMillis();
        }
        throw new UnexpectedException("Unsupported step " + step.name());
    }
Convert date in `yyyy-MM-dd HHmmss` style to `yyyyMMddHHmmss` no matter the precision. Such as, in day precision,
this covert `yyyy-MM-dd` style to `yyyyMMdd`.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/query/DurationUtils.java