Hadoop自带WordCount.java程序

最新推荐文章于 2021-02-28 09:10:28 发布

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最新推荐文章于 2021-02-28 09:10:28 发布 · 3.6k 阅读

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#Hadoop #WordCount #自带

本文介绍了Hadoop安装目录下自带的WordCount.java源代码的位置，它位于{Hadoop_HOME}hadoop-0.20.1srcexamplesorgapachehadoopexamples。这个例子是Hadoop初学者入门的经典教程，用于演示MapReduce的基本用法。

位置：{Hadoop_HOME}\hadoop-0.20.1\src\examples\org\apache\hadoop\examples\WordCount.java

其中{Hadoop_HOME}是安装后的Hadoop所在的目录

Hadoop自带WordCount程序：

package org.apache.hadoop.examples;

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 WordCount {

  public static class TokenizerMapper 
       extends Mapper<Object, Text, Text, IntWritable>{
    
    private final static IntWritable one = new IntWritable(1);
    private Text word = new Text();