Thanks Ramya.s I was trying it to do with NULLWRITABLE.. Thanks alot Ramya.
And do u have any idea how to sort a given col. Say if user is giving col2 to sort the i want to get as b,a,v a,c,p d,a,z q,z,a r,a,b b,a,v d,a,z r,a,b a,c,p q,z,a How do i approch to that. I my current implementation i am getting result as a,c,p b,a,v d,a,z q,z,a r,a,b using the above code. On Wed, Jan 15, 2014 at 5:09 PM, Ramya S <[email protected]> wrote: > All you need is to change the map output value class to TEXT format. > Set this accordingly in the main. > > Eg: > > public static class Map extends Mapper<LongWritable, Text, Text, Text> { > private Text one = new Text(""); > private Text word = new Text(); > > public void map(LongWritable key, Text value, Context context) throws > IOException, InterruptedException { > System.out.println("in mapper"); > String line = value.toString(); > StringTokenizer tokenizer = new StringTokenizer(line); > while (tokenizer.hasMoreTokens()) { > word.set(tokenizer.nextToken()); > context.write(word, one); > System.out.println("sort: "+word); > } > } > } > > Regards...? > Ramya.S > > > ________________________________ > > From: unmesha sreeveni [mailto:[email protected]] > Sent: Wed 1/15/2014 4:11 PM > To: User Hadoop > Subject: Re: Sorting a csv file > > > I did a map only job for sorting a txt file by editing wordcount program. > I only need the key . > How to set value to null. > > > public class SortingCsv { > public static class Map extends Mapper<LongWritable, Text, Text, > IntWritable> { > private final static IntWritable one = new IntWritable(1); > private Text word = new Text(); > > public void map(LongWritable key, Text value, Context context) throws > IOException, InterruptedException { > System.out.println("in mapper"); > String line = value.toString(); > StringTokenizer tokenizer = new StringTokenizer(line); > while (tokenizer.hasMoreTokens()) { > word.set(tokenizer.nextToken()); > context.write(word, one); > System.out.println("sort: "+word); > } > } > } > public static void main(String[] args) throws Exception { > System.out.println("in main"); > Configuration conf = new Configuration(); > > Job job = new Job(conf, "wordcount"); > job.setJarByClass(SortingCsv.class); > //Path intermediateInfo = new Path("out"); > job.setOutputKeyClass(Text.class); > job.setOutputValueClass(IntWritable.class); > > job.setMapperClass(Map.class); > FileSystem fs = FileSystem.get(conf); > > /* Delete the files if any in the output path */ > > if (fs.exists(new Path(args[1]))) > fs.delete(new Path(args[1]), true); > > > job.setInputFormatClass(TextInputFormat.class); > job.setOutputFormatClass(TextOutputFormat.class); > > FileInputFormat.addInputPath(job, new Path(args[0])); > FileOutputFormat.setOutputPath(job, new Path(args[1])); > > job.waitForCompletion(true); > } > > } > > > On Wed, Jan 15, 2014 at 2:50 PM, unmesha sreeveni <[email protected]> > wrote: > > > How to sort a csv file > I know , between map and reduce shuffle and sort is taking place. > But how do i sort each column in a csv file? > > > -- > > Thanks & Regards > > > Unmesha Sreeveni U.B > > Junior Developer > > http://www.unmeshasreeveni.blogspot.in/ > > > > > > > > > -- > > Thanks & Regards > > > Unmesha Sreeveni U.B > > Junior Developer > > http://www.unmeshasreeveni.blogspot.in/ > > > > > -- *Thanks & Regards* Unmesha Sreeveni U.B Junior Developer http://www.unmeshasreeveni.blogspot.in/
