package wc; import java.io.IOException; import java.util.*; import org.apache.hadoop.conf.*; import org.apache.hadoop.fs.*; import org.apache.hadoop.conf.*; import org.apache.hadoop.io.*; import org.apache.hadoop.mapreduce.*; import org.apache.hadoop.mapreduce.lib.input.*; import org.apache.hadoop.mapreduce.lib.output.*; import org.apache.hadoop.util.*; public class WordCount extends Configured implements Tool { public static void main(String args[]) throws Exception { int res = ToolRunner.run(new WordCount(), args); System.exit(res); } public int run(String[] args) throws Exception { Path inputPath = new Path(args[0]); Path outputPath = new Path(args[1]); Configuration conf = getConf(); Job job = new Job(conf, this.getClass().toString()); FileInputFormat.setInputPaths(job, inputPath); FileOutputFormat.setOutputPath(job, outputPath); job.setJobName("WordCount"); job.setJarByClass(WordCount.class); job.setInputFormatClass(TextInputFormat.class); job.setOutputFormatClass(TextOutputFormat.class); job.setMapOutputKeyClass(Text.class); job.setMapOutputValueClass(IntWritable.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); job.setMapperClass(Map.class); job.setCombinerClass(Reduce.class); job.setReducerClass(Reduce.class); return job.waitForCompletion(true) ? 0 : 1; } public static class Map extends Mapper { private final static IntWritable one = new IntWritable(1); private Text word = new Text(); @Override public void map(LongWritable key, Text value, Mapper.Context context) throws IOException, InterruptedException { String line = value.toString(); StringTokenizer tokenizer = new StringTokenizer(line); while (tokenizer.hasMoreTokens()) { word.set(tokenizer.nextToken()); context.write(word, one); } } } public static class Reduce extends Reducer { @Override public void reduce(Text key, Iterable values, Context context) throws IOException, InterruptedException { int sum = 0; for (IntWritable value : values) { sum += value.get(); } context.write(key, new IntWritable(sum)); } } }