hadoop - 在Hive中创建和使用UDF

Question

我创建了http://www.findnwrite.com/musings/extract-top-n-records-in-each-group-in-hadoophive/中提到的UDF

执行语句后，“将临时功能等级创建为'com.example.hive.udf.Rank';”
我得到的日志如http://pastebin.com/hHFa9G9A所示

如何解释日志或如何成功创建函数？

另外，当我使用函数等级执行配置单元查询时，也会得到如下异常:
http://pastebin.com/fP5LnyGG

Answer 1

这个问题解决了

文章本身的几个错误http://www.findnwrite.com/musings/extract-top-n-records-in-each-group-in-hadoophive/

用以下语句替换了本文中的语句

1)

Create Rank jar


jar -cf Rank.jar ./com/example/hive/udf/Rank.class

2)

SELECT user, category, value
FROM (
    SELECT user, category, rank(user) as rank, value
    FROM $compTable
    WHERE user is NOT NULL AND AND ctr > 0
    DISTRIBUTE BY user
    SORT BY user, value desc
) a
WHERE rank(user) < 5
ORDER BY user, rank(user)