public static String convertLongToDate(final long timestamp, final ZoneId zoneId) {
    return convertLongToDate(
        timestamp, CommonDescriptor.getInstance().getConfig().getTimestampPrecision(), zoneId);
  }
convert duration string to millisecond, microsecond or nanosecond.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/utils/DateTimeUtils.java