第一个MapReduce程序

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 java.io.IOException;

public class WordCountMap extends Mapper {
    @Override
    protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
        //读取每行文本
        String line =value.toString();
        //splite拆分每行
        String[] words =line.split("/t");
        //取出每个单词
        for(String word : words){
            //将单词转变为Text类型
            Text wordText = new Text(word);
            //将1转变为IntWritable
            IntWritable outValue = new IntWritable(1);
            //写出单词跟对应1
            context.write(wordText,outValue);
        }
    }
}