Hive UDFs
This article shows how to create a Hive UDF, register it in Spark, and use it in a Spark SQL query.
Here is a Hive UDF that takes a long
as an argument and returns its hexadecimal representation.
import org.apache.hadoop.hive.ql.exec.UDF
import org.apache.hadoop.io.LongWritable
// This UDF takes a long integer and converts it to a hexadecimal string.
class ToHex extends UDF {
def evaluate(n: LongWritable): String = {
Option(n)
.map { num =>
// Use Scala string interpolation. It's the easiest way, and it's
// type-safe, unlike String.format().
f"0x${num.get}%x"
}
.getOrElse("")
}
}
Register the function:
spark.sql("CREATE TEMPORARY FUNCTION to_hex AS 'com.ardentex.spark.hiveudf.ToHex'")
Use your function as any other registered function:
spark.sql("SELECT first_name, to_hex(code) as hex_code FROM people")
You can find more examples and compilable code at Sample Hive UDF project.