public static Long getLongVal(Object obj, long defaultVal) {
        if (obj == null) {
            return defaultVal;
        }

        return getLongVal(obj);
    }
Convert val to specified numeric type
Date: 2017/4/21
Company: www.dtstack.com
@author xuchao
core/src/main/java/com/dtstack/flink/sql/util/MathUtil.java