我编写了以下自定义项：
iso8601tohiveformat.java标准：

package hiveudfs;

import org.apache.hadoop.hive.ql.exec.UDF;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class ISO8601ToHiveFormat  extends UDF {

    public String hourFromISO8601(final String d){
        try{
            if( d == null )
                return null;
            SimpleDateFormat sdf1= new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
            SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            return sdf2.format(sdf1.parse(d)); 
        } catch (ParseException pe) {
            return null;
        }
    }
}

在我的项目的src文件夹中，我运行了以下compile命令来编译它：

javac -cp /usr/lib/hive/lib/hive-exec-0.10.0-cdh4.3.0.jar  ISO8601ToHiveFormat.java

我惊奇地把它装进一个jar里

jar cf ../../HiveUDFs.jar hiveudfs/ISO8601ToHiveFormat.*

所以，我开始做Hive并做了：

hive> add jar /home/tom/Java/HiveUDFs.jar;
Added /home/tom/Java/HiveUDFs.jar to class path
Added resource: /home/tom/Java/HiveUDFs.jar
hive> create temporary function hourFromISO8601 as 'hiveudfs.ISO8601ToHiveFormat';
OK
Time taken: 0.083 seconds
hive> SELECT hourFromISO8601(logtimestamp) FROM mytable LIMIT 10;
FAILED: SemanticException [Error 10014]: Line 1:7 Wrong arguments 'logtimestamp': No matching method for class hiveudfs.ISO8601ToHiveFormat with (string). Possible choices: 
hive>

输出

hive> describe mytable;
OK
...
logtimestamp    string
...

我做错什么了？