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<LongWritable, Text, Text, IntWritable> {
?? ??? ?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<Text, IntWritable, Text, IntWritable> {
?? ??? ?public void reduce(Text key, Iterable<IntWritable> 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);
?? ?}
}