Hadoop-4、Mapred数据去重

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
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 DelRep {
    public static class Map extends Mapper<Object,Text,Text,Text>{
        private static Text line = new Text();
        public void map(Object key,Text value,Context context) throws IOException, InterruptedException{
            line = value;
            context.write(line, new Text(""));
        }
    }
    
    public static class Reduce extends Reducer<Text,Text,Text,Text>{
        public void reduce(Text key,Iterable<Text> value,Context context) throws IOException, InterruptedException{
            context.write(key, new Text(""));
        }
    }
    
    public static void main(String[] Args) throws IOException, ClassNotFoundException, InterruptedException{
        Configuration conf = new Configuration();
        conf.addResource(new Path("/usr/hadoop-1.0.3/conf/core-site.xml"));
        
        String[] otherArgs = new GenericOptionsParser(conf,Args).getRemainingArgs();
        
        Job job = new Job(conf,"DelRep");
        
        job.setJarByClass(DelRep.class);
        
        job.setMapperClass(Map.class);
        job.setCombinerClass(Reduce.class);
        job.setReducerClass(Reduce.class);
        
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);
        
        FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
        FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
        
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}

File1：

2006-6-9 a
2006-6-10 b
2006-6-11 c
2006-6-12 d
2006-6-13 a
2006-6-14 b
2006-6-15 c
2006-6-11 c

File2

2006-6-9 d
2006-6-10 a
2006-6-11 b
2006-6-12 d
2006-6-13 a
2006-6-14 c
2006-6-15 d
2006-6-11 c

结果：

2006-6-10 a	
2006-6-10 b	
2006-6-11 b	
2006-6-11 c	
2006-6-12 d	
2006-6-13 a	
2006-6-14 b	
2006-6-14 c	
2006-6-15 c	
2006-6-15 d	
2006-6-9 a	
2006-6-9 d