ProSel.java

import java.io.IOException;
import java.util.*;

import org.apache.hadoop.conf.*;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapreduce.*;
import org.apache.hadoop.mapreduce.lib.input.*;
import org.apache.hadoop.mapreduce.lib.output.*;
import org.apache.hadoop.util.GenericOptionsParser;

public class ProSel
{

	public static class ProSelMapper extends Mapper<Object, Text, Text, Text>
	{
		private Text word = new Text();
		private Text result = new Text(new byte[0]);
		public void map(Object key, Text value, Context context) throws IOException, InterruptedException 
		{
			StringTokenizer itr = new StringTokenizer(value.toString(), "|");
			if(itr.countTokens() < 4) return;
			
			String emp_id = itr.nextToken().trim();
			String dept_id = itr.nextToken().trim();
			
			int salary = Integer.parseInt(itr.nextToken().trim());
			
			String emp_info = itr.nextToken().trim();
			
			if(salary >= 3500000) {
				word.set(new byte[0]);
				word.set(emp_id + "|" + salary);
				context.write(word, result);
			}
		}
	}

	// REDUCER 필요없음
	
	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: ProSel <in> <out>");
			System.exit(2);
		}
		Job job = new Job(conf, "ProSel");
		job.setJarByClass(ProSel.class);
		job.setMapperClass(ProSelMapper.class);
		job.setNumReduceTasks(0); // reduce 사용 안 한다는 뜻
		job.setOutputKeyClass(Text.class);
		job.setOutputValueClass(Text.class);
		FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
		FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
		FileSystem.get(job.getConfiguration()).delete( new Path(otherArgs[1]), true);
		System.exit(job.waitForCompletion(true) ? 0 : 1);
	}
}