hive UDF 的使用

首先要继承org.apache.hadoop.hive.ql.exec.UDF类实现 evaluate

自定义函数调用过程：

1. 添加jar包（在hive命令行里面执行)

   hive> add jar /root/NUDF.jar;

2. 创建临时函数

   hive> create temporary function getNation as 'com.hw.hive.udf.NationUDF';

3. 调用

   hive> select id, name, getNation(nation) from beauty;

4. 将查询结果保存到HDFS中

   hive> create table result row format delimited fields terminated by '\t' as select * from beauty order by id desc;
hive> select id, getAreaName(id) as name from tel_rec;

   create table result row format delimited fields terminated by '\t' as select id, getNation(nation) from beauties;