You might want to provide the jar file which has your class in the class path in the USING clause. Something like:
USING 'java -cp /path/to/your/jar WeekdayMapper' On 5/24/09 10:50 PM, "Manhee Jo" <[email protected]> wrote: > Thank you Zheng, > Here is my WeekdayMapper.java, which is just a test that does almost same > thing as the "weekday_mapper.py" does. > As you see below, it does not take WritableComparable nor Writable class. It > receives the 4 columns just string > arguments. Any advice would be very appreciated. > > /** > * WeekdayMapper.java > */ > > import java.io.*; > import java.util.*; > > class WeekdayMapper { > public static void main (String[] args) throws IOException { > Scanner stdIn = new Scanner(System.in); > String line=null; > String[] column; > long unixTime; > Date d; > GregorianCalendar cal1 = new GregorianCalendar(); > > while (stdIn.hasNext()) { > line = stdIn.nextLine(); > column = line.split("\t"); > unixTime = Long.parseLong(column[3]); > d = new Date(unixTime*1000); > cal1.setTime(d); > int dow = cal1.get(Calendar.DAY_OF_WEEK); > System.out.println(column[0] + "\t" + column[1] + "\t" > + column[2] + "\t" + dow); > } > } > } > > Thanks, > Manhee > >> >> ----- Original Message ----- >> >> From: Zheng Shao <mailto:[email protected]> >> >> To: [email protected] >> >> Sent: Monday, May 25, 2009 10:28 AM >> >> Subject: Re: Hive and Hadoop streaming >> >> >> How do your java map function receive the 4 columns? >> I assume your java map function takes a WritableComparable key and Writable >> value. >> >> Zheng >> >> >> 2009/5/24 Manhee Jo <[email protected]> >> >>> >>> >>> I have some mappers already coded in Java. So I want to use it >>> >>> as much as possible in Hive environment. >>> >>> Then, how can I call a Java mapper to "select transform" in Hive? >>> >>> For example, what is wrong with the query below and why? >>> >>> >>> >>> INSERT OVERWRITE TABLE u_data_new >>> SELECT >>> TRANSFORM (userid, movieid, rating, unixtime) >>> USING 'java WeekdayMapper' >>> AS (userid, movieid, rating, weekday) >>> FROM u_data; >>> >>> Thank you. >>> >>> >>> >>> >>> >>> Regards, >>> >>> Manhee >> >> >> >> -- >> Yours, >> Zheng
