Ohh, thank you loan Eugen stan and Doug. I forgot to notice that, as i had been working with programs , where they had to be null. Thank you.
On Sat, Jan 28, 2012 at 7:05 PM, Doug Meil <doug.m...@explorysmedical.com>wrote: > > In addition, see... > > http://hbase.apache.org/book.html#mapreduce.example > > > > > > On 1/28/12 6:43 AM, "Ioan Eugen Stan" <stan.ieu...@gmail.com> wrote: > > >2012/1/28 Vamshi Krishna <vamshi2...@gmail.com>: > >> Hi, here i am trying to read rows from a table, and put them to a file > >>as > >> it is.For that my mapper class and run method are as shown below. > >>(Correct > >> me if any thing wrong). > >> > >> public static class SIMapper extends > >> TableMapper<ImmutableBytesWritable,Text> { > >> Configuration config=HBaseConfiguration.create(); > >> > >> private Text TABLE=new Text("HS3"); > >> > >> public void map(ImmutableBytesWritable row, Text value, Context > >> context) throws IOException { > >> > >> try { > >> context.write(row, TABLE); > >> } catch (InterruptedException e) { > >> throw new IOException(e); > >> } > >> > >> } > >> > >> } > >> > >> > >> Run method:--- > >> > >> public int run(String[] args) throws Exception { > >> > >> Job job = new Job(getConf()); > >> job.setJobName("Job-1"); > >> job.setJarByClass(setjar.class); > >> > >> Scan s=new Scan(); > >> s.setCacheBlocks(false); > >> s.setCaching(1000); > >> > >> TableMapReduceUtil.initTableMapperJob(args[0],s, SIMapper.class, > >> null,null, job); // args[0] is the table name, which is the input table > >> for mapper. > >> TableMapReduceUtil.addDependencyJars(job); > >> > >> FileOutputFormat.setOutputPath(job, new Path(args[1])); > >> > >> > >> return job.waitForCompletion(true)? 0:1 ; > >> } > >> > >> When i try to execute the job, i am getting following error. I don't > >>know > >> what is the mistake.For what the LongWritable it is expected? > >> > >> 12/01/28 11:57:23 INFO mapred.JobClient: map 0% reduce 0% > >> 12/01/28 11:57:34 INFO mapred.JobClient: Task Id : > >> attempt_201201281010_0004_m_000000_0, Status : FAILED > >> java.io.IOException: Type mismatch in key from map: expected > >> org.apache.hadoop.io.LongWritable, recieved > >> org.apache.hadoop.hbase.io.ImmutableBytesWritable > >> at > >> > >>org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:845 > >>) > >> at > >> > >>org.apache.hadoop.mapred.MapTask$NewOutputCollector.write(MapTask.java:54 > >>1) > >> at > >> > >>org.apache.hadoop.mapreduce.TaskInputOutputContext.write(TaskInputOutputC > >>ontext.java:80) > >> at org.apache.hadoop.mapreduce.Mapper.map(Mapper.java:124) > >> at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144) > >> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:621) > >> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:305) > >> at org.apache.hadoop.mapred.Child.main(Child.java:170) > >> > >> please some body help.. > >> > >> -- > >> *Regards* > >> * > >> Vamshi Krishna > >> * > > > >You have to replace the two null values from initTableMapper with the > >classes that you have for key and value. Please see javadoc for > >TableMapReduceUtil class [1]. > > > >[1] > > > http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/mapreduce/TableMap > >ReduceUtil.html > >-- > >Ioan Eugen Stan > >http://ieugen.blogspot.com/ > > > > > -- *Regards* * Vamshi Krishna *
