private int convertToTime(BsonValue docObj) {
        if (docObj.isDateTime()) {
            Instant instant = convertToInstant(docObj.asDateTime());
            return convertInstantToLocalTime(instant).toSecondOfDay() * 1000;
        }
        if (docObj.isTimestamp()) {
            Instant instant = convertToInstant(docObj.asTimestamp());
            return convertInstantToLocalTime(instant).toSecondOfDay() * 1000;
        }
        throw new IllegalArgumentException(
                "Unable to convert to time from unexpected value '"
                        + docObj
                        + "' of type "
                        + docObj.getBsonType());
    }
A conversion from TimeType to int describes the number of milliseconds of the day.
inlong-sort/sort-flink/sort-flink-v1.15/sort-connectors/mongodb-cdc/src/main/java/org/apache/inlong/sort/mongodb/MongoDBConnectorDeserializationSchema.java