private BigDecimal truncate(BigDecimal numeric1) {
        if (numeric1 == null) {
            return null;
        }
        return numeric1.setScale(0, RoundingMode.DOWN);
    }
TruncateFunction  ->  truncate(numeric, cnt)
description:
- Return NULL if any parameter is NULL;
- Return the result of truncating 'numeric' values to 'cnt' decimal places.
inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/arithmetic/TruncateFunction.java