package com.hadoop.sample; import java.io.IOException; import java.util.StringTokenizer; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; 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 Dedup { //map将输入中的value复制到输出数据的key上,并直接输出 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("")); } } //reduce将输入中的key复制到输出数据的key上,并直接输出 public static class Reduce extends Reducer<Text,Text,Text,Text>{ public void reduce(Text key,Iterable<Text> values,Context context) throws IOException,InterruptedException{ context.write(key, new Text("")); } } /** * @param args */ public static void main(String[] args) throws Exception{ // TODO Auto-generated method stub Configuration conf = new Configuration(); String[] otherArgs = new GenericOptionsParser(conf,args).getRemainingArgs(); if(otherArgs.length != 2){ System.err.println("Usage WordCount <int> <out>"); System.exit(2); } Job job = new Job(conf,"Dedup"); job.setJarByClass(Dedup.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); } }
hadoop--mapredduce代码之数据去重
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