content: package com.manning.hip.ch5;
  
  import org.apache.avro.generic.GenericRecord;
  import org.apache.avro.mapred.*;
  import org.apache.commons.codec.digest.DigestUtils;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.io.NullWritable;
  import org.apache.hadoop.io.Text;
  import org.apache.hadoop.mapred.*;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  
  public class SmallFilesMapReduce {
  
    public static void main(String... args) throws Exception {
      JobConf job = new JobConf();
      job.setJarByClass(SmallFilesMapReduce.class);
      Path input = new Path(args[0]);
      Path output = new Path(args[1]);
  
      output.getFileSystem(job).delete(output, true);
  
      job.set(AvroJob.INPUT_SCHEMA, SmallFilesWrite.SCHEMA.toString());
  
      job.setInputFormat(AvroInputFormat.class);
  
      job.setOutputFormat(TextOutputFormat.class);
  
      job.setMapperClass(Map.class);
      FileInputFormat.setInputPaths(job, input);
      FileOutputFormat.setOutputPath(job, output);
  
      job.setNumReduceTasks(0);
  
      JobClient.runJob(job);
    }
  
     public static class Map
        implements
        Mapper<AvroWrapper<GenericRecord>, NullWritable, Text, Text> {
  
       private Text outKey = new Text();
       private Text outValue = new Text();
  
      public void map(AvroWrapper<GenericRecord> key,
                      NullWritable value,
                      OutputCollector<Text, Text> output,
                      Reporter reporter) throws IOException {
        outKey.set(
          key.datum().get(SmallFilesWrite.FIELD_FILENAME).toString());
        outValue.set(DigestUtils.md5Hex(
              ((ByteBuffer) key.datum().get(SmallFilesWrite.FIELD_CONTENTS))
                .array()));
  
        output.collect(outKey, outValue);
      }
  
      public void close() throws IOException {
      }
  
      public void configure(JobConf job) {
      }
    }
  }