Hi Mark
public void map(LongWritable offset, Text
val,OutputCollector<
FloatWritable,Text> output, Reporter reporter)
throws IOException {
output.collect(new FloatWritable(*1*), val); *//chanage 1 to 1.0f
then it will work.*
}
let me know the status after the change
On Wed, May 30, 2012 at 1:27 AM, Mark question <markq2...@gmail.com> wrote:
> Hi guys, this is a very simple program, trying to use TextInputFormat and
> SequenceFileoutputFormat. Should be easy but I get the same error.
>
> Here is my configurations:
>
> conf.setMapperClass(myMapper.class);
> conf.setMapOutputKeyClass(FloatWritable.class);
> conf.setMapOutputValueClass(Text.class);
> conf.setNumReduceTasks(0);
> conf.setOutputKeyClass(FloatWritable.class);
> conf.setOutputValueClass(Text.class);
>
> conf.setInputFormat(TextInputFormat.class);
> conf.setOutputFormat(SequenceFileOutputFormat.class);
>
> TextInputFormat.addInputPath(conf, new Path(args[0]));
> SequenceFileOutputFormat.setOutputPath(conf, new Path(args[1]));
>
>
> myMapper class is:
>
> public class myMapper extends MapReduceBase implements
> Mapper<LongWritable,Text,FloatWritable,Text> {
>
> public void map(LongWritable offset, Text
> val,OutputCollector<FloatWritable,Text> output, Reporter reporter)
> throws IOException {
> output.collect(new FloatWritable(1), val);
> }
> }
>
> But I get the following error:
>
> 12/05/29 12:54:31 INFO mapreduce.Job: Task Id :
> attempt_201205260045_0032_m_000000_0, Status : FAILED
> java.io.IOException: wrong key class: org.apache.hadoop.io.LongWritable is
> not class org.apache.hadoop.io.FloatWritable
> at
> org.apache.hadoop.io.SequenceFile$Writer.append(SequenceFile.java:998)
> at
>
> org.apache.hadoop.mapred.SequenceFileOutputFormat$1.write(SequenceFileOutputFormat.java:75)
> at
>
> org.apache.hadoop.mapred.MapTask$DirectMapOutputCollector.collect(MapTask.java:705)
> at
>
> org.apache.hadoop.mapred.MapTask$OldOutputCollector.collect(MapTask.java:508)
> at
>
> filter.stat.cosine.preprocess.SortByNorm1$Norm1Mapper.map(SortByNorm1.java:59)
> at
>
> filter.stat.cosine.preprocess.SortByNorm1$Norm1Mapper.map(SortByNorm1.java:1)
> at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:54)
> at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:397)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:330)
> at org.apache.hadoop.mapred.Child$4.run(Child.java:217)
> at java.security.AccessController.doPrivileged(Native Method)
> at javax.security.auth.Subject.doAs(Subject.java:396)
> at org.apache.hadoop.security.Use
>
> Where is the writing of LongWritable coming from ??
>
> Thank you,
> Mark
>
