FirstMapper

package com.sxt.hadoop.mr.tfidf;

import java.io.IOException;
import java.io.StringReader;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.wltea.analyzer.core.IKSegmenter;
import org.wltea.analyzer.core.Lexeme;

/**
 * 第一个MR，计算TF和计算N(微博总数)
 * 
 * @author root
 *
 */
public class FirstMapper extends Mapper<LongWritable, Text, Text, IntWritable> {

	protected void map(LongWritable key, Text value, Context context)
			throws IOException, InterruptedException {
		//3823890210294392	今天我约了豆浆，油条
		String[] v = value.toString().trim().split("\t");
		if (v.length >= 2) {
			String id = v[0].trim();
			String content = v[1].trim();
			StringReader sr = new StringReader(content);
			IKSegmenter ikSegmenter = new IKSegmenter(sr, true);
			Lexeme word = null;
			while ((word = ikSegmenter.next()) != null) {
				String w = word.getLexemeText();
				context.write(new Text(w + "_" + id), new IntWritable(1));
				//今天_3823890210294392	1
			}
			context.write(new Text("count"), new IntWritable(1));
			//count 1
		} else {
			System.out.println(value.toString() + "-------------");
		}
	}

}