multipleOutputs Hadoop

package org.lukey.hadoop.muloutput;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
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.FileSplit;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.MultipleOutputs;
import org.apache.hadoop.util.GenericOptionsParser;

public class TestMultipleOutput {

    static String baseOutputPath = "/user/hadoop/test_out";

    private static MultipleOutputs<Text, IntWritable> mos;

    // Mapper
    static class WordsOfClassCountMapper extends Mapper<LongWritable, Text, Text, IntWritable> {

        private final static IntWritable one = new IntWritable(1);
        private Text className = new Text();

        @Override
        protected void map(LongWritable key, Text value, Mapper<LongWritable, Text, Text, IntWritable>.Context context)
                throws IOException, InterruptedException {
            // TODO Auto-generated method stub
            FileSplit fileSplit = (FileSplit) context.getInputSplit();

            // 文件名
            String fileName = fileSplit.getPath().getName();

            // 文件夹名
            String dirName = fileSplit.getPath().getParent().getName();

            className.set(dirName + "/" + fileName);

            // Country:ABDBI 1
            mos.write(value, one, className.toString());
            // context.write(className, one);

        }

        @Override
        protected void cleanup(Mapper<LongWritable, Text, Text, IntWritable>.Context context)
                throws IOException, InterruptedException {
            // TODO Auto-generated method stub
            mos.close();
        }

        @Override
        protected void setup(Mapper<LongWritable, Text, Text, IntWritable>.Context context)
                throws IOException, InterruptedException {
            // TODO Auto-generated method stub
            mos = new MultipleOutputs<Text, IntWritable>(context);
        }

    }

    // Reducer
    static class WordsOfClassCountReducer extends Reducer<Text, IntWritable, Text, IntWritable> {

        // result 表示每个文件里面单词个数
        IntWritable result = new IntWritable();

        @Override
        protected void reduce(Text key, Iterable<IntWritable> values,
                Reducer<Text, IntWritable, Text, IntWritable>.Context context)
                        throws IOException, InterruptedException {
            // TODO Auto-generated method stub
            int sum = 0;
            for (IntWritable value : values) {
                sum += value.get();
            }
            result.set(sum);

            context.write(key, result);
        }

    }

    // Client
    public static void main(String[] args) throws Exception {

        Configuration conf = new Configuration();

        String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();

        if (otherArgs.length != 2) {
            System.out.println("Usage <in> <out>");
            System.exit(-1);
        }

        Job job = new Job(conf, "file count");

        job.setJarByClass(TestMultipleOutput.class);

        job.setMapperClass(WordsOfClassCountMapper.class);
        job.setReducerClass(WordsOfClassCountReducer.class);

        FileSystem fileSystem = FileSystem.get(conf);

        Path path = new Path(otherArgs[0]);

        FileStatus[] fileStatus = fileSystem.listStatus(path);

        for (FileStatus fs : fileStatus) {
            if (fs.isDir()) {
                Path p = new Path(fs.getPath().toString());
                FileInputFormat.addInputPath(job, p);
            }else{
                FileInputFormat.addInputPath(job, fs.getPath());
            }
        }

        FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));

        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);

        System.exit(job.waitForCompletion(true) ? 0 : 1);

    }
}