content: package com.manning.hip.ch3.passwd;
  
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.io.LongWritable;
  import org.apache.hadoop.io.NullWritable;
  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.output.FileOutputFormat;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  
  public final class PasswdMapReduce {
    private static final Logger log = LoggerFactory.getLogger(
        PasswdMapReduce.class);
  
    public static class Map extends Mapper<LongWritable, Passwd,
        Text, Passwd> {
      private Text redKey = new Text();
      @Override
      protected void map(LongWritable key, Passwd value,
                         Context context)
          throws
          IOException, InterruptedException {
        redKey.set(value.getUsername());
        context.write(redKey, value);
      }
    }
  
    public static class Reduce
        extends Reducer<Text, Passwd, Passwd, NullWritable> {
  
      public void reduce(Text key, Iterable<Passwd> values,
                         Context context)
          throws IOException, InterruptedException {
        for (Passwd val : values) {
          log.info(val.toString());
          context.write(val, NullWritable.get());
        }
        //throw new IOException();
      }
    }
  
    public static void main(String... args) throws Exception {
      runJob(args[0], args[1]);
    }
  
    public static void runJob(String input,
                              String output)
        throws Exception {
      Configuration conf = new Configuration();
  
      Job job = new Job(conf);
      job.setJarByClass(PasswdMapReduce.class);
      job.setMapperClass(Map.class);
      job.setReducerClass(Reduce.class);
      job.setInputFormatClass(PasswdInputFormat.class);
      job.setOutputFormatClass(PasswdOutputFormat.class);
  
      job.setMapOutputKeyClass(Text.class);
      job.setMapOutputValueClass(Passwd.class);
  
      FileInputFormat.setInputPaths(job, new Path(input));
      Path outPath = new Path(output);
      FileOutputFormat.setOutputPath(job, outPath);
  
      outPath.getFileSystem(conf).delete(outPath, true);
  
      job.waitForCompletion(true);
    }
  }
  