Home | About | Sematext search-lucene.com search-hadoop.com
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB
 Search Hadoop and all its subprojects:

Switch to Plain View
Hadoop >> mail # user >> old problem: mapper output as sequence file


+
Shi Yu 2011-09-19, 19:19
Copy link to this message
-
Re: old problem: mapper output as sequence file
Hi,

On Mon, Sep 19, 2011 at 3:19 PM, Shi Yu <[EMAIL PROTECTED]> wrote:
>
> I am stuck again in a probably very simple problem.  I couldn't generate the
> map output in sequence file format.  I always get this error:
> java.io.IOException: wrong key class: org.apache.hadoop.io.Text is not class org.apache.hadoop.io.LongWritable
No worries.

>        job.setMapOutputKeyClass(Text.class);
>        job.setMapOutputValueClass(Text.class);

You are running a map only job, so I think you want:

       job.setOutputKeyClass(Text.class);
       job.setOutputValueClass(Text.class);

But I also recommend adding @Override on your map method because it's
easy to accidentally not override your superclass method.

         @Override
          public void map(LongWritable key, Text value, Context context)
         throws IOException, InterruptedException{
Brock
+
Shi Yu 2011-09-19, 20:28
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB