按照艺术家分组并输出某个艺术家的唯一键值对

/***
 * @author YangXin
 * @info 按照艺术家分组并输出某个艺术家的唯一键-值对
 * Mapper输出艺术家，而Reducer只输出唯一的艺术家并丢弃空的字符值。
 */
package unitTwelve;

import java.io.IOException;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;

public class DirectoryReducer extends Reducer<Text, IntWritable, Text, IntWritable>{
    @Override
    protected void reduce(Text artist, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException{
        context.write(artist, new IntWritable(0));
    }
}