Hadoop--单词统计

package com.smartmap.example;

import java.io.IOException;
import java.util.StringTokenizer;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
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.apache.hadoop.util.GenericOptionsParser;

public class WordCount {
	public static class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable>
	{
		private final static IntWritable one = new IntWritable(1);
		private Text word = new Text();
		
		public void map(Object key, Text value, Context context) throws IOException, InterruptedException
		{
			StringTokenizer stringTokenizer = new StringTokenizer(value.toString());
			while(stringTokenizer.hasMoreTokens())
			{
				word.set(stringTokenizer.nextToken());
				context.write(word, one);
			}
		}
	}
	
	public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable>
	{
		private final static IntWritable result = new IntWritable();
		public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException
		{
			int sum = 0;
			for(IntWritable val : values)
			{
				sum += val.get();
			}
			result.set(sum);
			context.write(key, result);
		}
	}
	
	public static void main(String[] args) throws Exception
	{
		Configuration conf = new Configuration();
		String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
		if(otherArgs.length != 2)
		{
			System.err.println("Usage: wordcount <int> <out>");
			System.exit(2);
		}
		Job job = new Job(conf, "word count");
		job.setJarByClass(WordCount.class);
		job.setMapperClass(TokenizerMapper.class);
		job.setCombinerClass(IntSumReducer.class);
		job.setReducerClass(IntSumReducer.class);
		job.setOutputKeyClass(Text.class);
		job.setOutputValueClass(IntWritable.class);
		
		
		FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
		FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
		System.exit(job.waitForCompletion(true)? 0 : 1);
	}
}

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hdfs://192.168.1.30:9000/data/word /opt/eclipse/workspace/data/out