How to create UDF (User Defined Function) in Hive

1. User Defined Function (UDF) in Hive using Java.

2. Download hive-0.4.1.jar and add it to lib-> Buil Path -> Add jar to libraries

3. Q:Find the Cube of number passed:

import org.apache.hadoop.hive.ql.exec.UDF;

public class Cube extends UDF{

public int evaluate (int number)
{
return number*number*number;
}
}

4. Create jar file and copy to HDFS
terminal > sudo hadoop fs -put /home/cloudera/Desktop/Cube.jar /user/cloudera/

5. ADD JAR EXPORTED_FILE_NAME.jar;
hive> ADD JAR hdfs://quickstart.cloudera:8020/user/cloudera/Cube.jar;

6. hive> list jars;

7. Create Temperory function:
CREATE temporary function func_name as ‘absolute_class_name’.
hive> CREATE temporary function Cube as ‘Cube’;

8. hive> select Cube(marks) from student;

9. Create Permenent Function:
hive> CREATE function Cube as ‘Cube’ using jar ‘hdfs://quickstart.cloudera:8020/user/cloudera/Cube.jar’;

10. hive> select Cube(marks) from student;