hadoop demo

import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;

public class WordCount {
	public static class WordCountMap extends
			Mapper
 
   {
		private final IntWritable one = new IntWritable(1);
		private Text word = new Text();

		public void map(LongWritable key, Text value, Context context)
				throws IOException, InterruptedException {
			String line = value.toString();
			StringTokenizer token = new StringTokenizer(line);
			while (token.hasMoreTokens()) {
				word.set(token.nextToken());
				context.write(word, one);
			}
		}
	}

	public static class WordCountReduce extends
			Reducer
  
    { public void reduce(Text key, Iterable
   
     values, Context context) throws IOException, InterruptedException { int sum = 0; for (IntWritable val : values) { sum += val.get(); } context.write(key, new IntWritable(sum)); } } public static void main(String[] args) throws Exception { Configuration conf = new Configuration(); Job job = new Job(conf); job.setJarByClass(WordCount.class); job.setJobName("wordcount"); job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); job.setMapperClass(WordCountMap.class); job.setReducerClass(WordCountReduce.class); 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); } }
   
  
 

import java.io.IOException;

import java.util.StringTokenizer;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Job;

import org.apache.hadoop.mapreduce.Mapper;

import org.apache.hadoop.mapreduce.Reducer;

import org.apache.hadoop.mapreduce.Partitioner;

import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;

import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import org.apache.hadoop.util.GenericOptionsParser;

public class Sort {

	public static class Map extends
			Mapper
 
   {

		private static IntWritable data = new IntWritable();

		public void map(Object key, Text value, Context context)
				throws IOException, InterruptedException {
			String line = value.toString();

			data.set(Integer.parseInt(line));

			context.write(data, new IntWritable(1));

		}

	}

	public static class Reduce extends
			Reducer
  
    { private static IntWritable linenum = new IntWritable(1); public void reduce(IntWritable key, Iterable
   
     values, Context context) throws IOException, InterruptedException { for (IntWritable val : values) { context.write(linenum, key); linenum = new IntWritable(linenum.get() + 1); } } } public static class Partition extends Partitioner
    
      { @Override public int getPartition(IntWritable key, IntWritable value, int numPartitions) { int MaxNumber = 65223; int bound = MaxNumber / numPartitions + 1; int keynumber = key.get(); for (int i = 0; i < numPartitions; i++) { if (keynumber < bound * i && keynumber >= bound * (i - 1)) return i - 1; } return 0; } } /** * @param args */ public static void main(String[] args) throws Exception { // TODO Auto-generated method stub Configuration conf = new Configuration(); String[] otherArgs = new GenericOptionsParser(conf, args) .getRemainingArgs(); if (otherArgs.length != 2) { System.err.println("Usage WordCount 
      
      
       "); System.exit(2); } Job job = new Job(conf, "Sort"); job.setJarByClass(Sort.class); job.setMapperClass(Map.class); job.setPartitionerClass(Partition.class); job.setReducerClass(Reduce.class); job.setOutputKeyClass(IntWritable.class); job.setOutputValueClass(IntWritable.class); FileInputFormat.addInputPath(job, new Path(otherArgs[0])); FileOutputFormat.setOutputPath(job, new Path(otherArgs[1])); System.exit(job.waitForCompletion(true) ? 0 : 1); } }