public static ZonedDateTime convertMillsecondToZonedDateTime(long millisecond) {
    return ZonedDateTime.ofInstant(Instant.ofEpochMilli(millisecond), ZoneId.systemDefault());
  }
convert duration string to millisecond, microsecond or nanosecond.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/utils/DateTimeUtils.java