利用MultipleOutputs控制reduce输出路径

利用MultipleOutputs控制reduce输出路径

package com.mr.test;
import java.io.IOException;
import java.util.Iterator;
import java.util.StringTokenizer;

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.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.TextInputFormat;
import org.apache.hadoop.mapred.TextOutputFormat;
import org.apache.hadoop.mapred.lib.MultipleOutputs;

public class WordCount {
    public static class MyMap implements
            Mapper<LongWritable, Text, Text, IntWritable> {
        private final static IntWritable one = new IntWritable(1);
        private Text word = new Text();
        
        public void map(LongWritable key, Text value,
                OutputCollector<Text, IntWritable> output, Reporter reporter)
                throws IOException {
            String line = value.toString();
            StringTokenizer tokenizer = new StringTokenizer(line);
            while (tokenizer.hasMoreTokens()) {
                word.set(tokenizer.nextToken());
                output.collect(word, one);
            }
        }
		public void configure(JobConf arg0) {
			
		}
		public void close() throws IOException {
			// TODO Auto-generated method stub
		}
    }

    public static class MyReduce implements
            Reducer<Text, IntWritable, Text, IntWritable> {
    	private MultipleOutputs mos;
    	private JobConf jobconf;
        public void reduce(Text key, Iterator<IntWritable> values,
                OutputCollector<Text, IntWritable> output, Reporter reporter)
                throws IOException {
            int sum = 0;
            while (values.hasNext()) {
                sum += values.next().get();
            }
            mos.getCollector(key.toString(), reporter).collect(key, new IntWritable(sum));
//            mos.getCollector(key.toString(),"test", reporter).collect(key, new IntWritable(sum));
        }

		public void configure(JobConf jobconf) {
			mos = new MultipleOutputs(jobconf);
			this.jobconf = jobconf;
		}

		public void close() throws IOException {
			mos.close();
		}
    }

    public static void main(String[] args) throws Exception {
        JobConf conf = new JobConf(WordCount.class);
        conf.setJobName("wordcount");

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

        conf.setMapperClass(MyMap.class);
        conf.setCombinerClass(MyReduce.class);
        conf.setReducerClass(MyReduce.class);

        conf.setInputFormat(TextInputFormat.class);
        conf.setOutputFormat(TextOutputFormat.class);
		System.out.println("args1:"+args[0]);
		System.out.println("args2:"+args[1]);
        FileInputFormat.setInputPaths(conf, new Path(args[0]));
        FileOutputFormat.setOutputPath(conf, new Path(args[1]));
        MultipleOutputs.addNamedOutput(conf, "test1", TextOutputFormat.class,
        		 LongWritable.class, Text.class);
        MultipleOutputs.addNamedOutput(conf, "test2", TextOutputFormat.class,
       		 LongWritable.class, Text.class);
        MultipleOutputs.addNamedOutput(conf, "test3", TextOutputFormat.class,
       		 LongWritable.class, Text.class);
        MultipleOutputs.addNamedOutput(conf, "test4", TextOutputFormat.class,
       		 LongWritable.class, Text.class);
        MultipleOutputs.addNamedOutput(conf, "test5", TextOutputFormat.class,
       		 LongWritable.class, Text.class);
        JobClient.runJob(conf);
    }
}

input.txt:

test1
test2
test3
test4
test5

output:

-rw-r--r--   2 test supergroup          0 2014-04-20 11:23 /chukwa/output/0419-10/_SUCCESS
drwxr-xr-x   - test supergroup          0 2014-04-20 11:23 /chukwa/output/0419-10/_logs
-rw-r--r--   2 test supergroup         42 2014-04-20 11:23 /chukwa/output/0419-10/part-00000.lzo
-rw-r--r--   2 test supergroup         58 2014-04-20 11:23 /chukwa/output/0419-10/test1-m-00000.lzo
-rw-r--r--   2 test supergroup         58 2014-04-20 11:23 /chukwa/output/0419-10/test2-m-00000.lzo
-rw-r--r--   2 test supergroup         58 2014-04-20 11:23 /chukwa/output/0419-10/test3-m-00000.lzo
-rw-r--r--   2test supergroup         58 2014-04-20 11:23 /chukwa/output/0419-10/test4-m-00001.lzo
-rw-r--r--   2 test supergroup         58 2014-04-20 11:23 /chukwa/output/0419-10/test5-m-00001.lzo