介绍 package com.test;
import java.io.IOException;
import java.util.Iterator;
import java.util.StringTokenizer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.GenericWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
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.KeyValueTextInputFormat;
import org.apache.hadoop.mapreduce.lib.input.MultipleInputs;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;/* *
,*业务场景:
,*含有两个文件,两个文件中单词之间的分隔方式不一样,但是统计出单词在两个文件中公共出现的次数
*大敌;
1,*文件来源,逗号分隔text1.txt
,*,你好,什么
,*你,哈哈
2,*文件来源,制表符分隔text2.txt
,* girl 男孩
,* father 母亲
,*/public class WordCountGenericWritable extends Configured implements Tool {
,
,public static class Map1 extends Mapper, {
public 才能;void 地图(LongWritable 关键,Text 价值,Context 上下文),throws IOException, InterruptedException {
,,String line =, value.toString ();
,,
,,StringTokenizer st =, new StringTokenizer (,,,,,);
,,,(st.hasMoreElements ()), {
,,,context.write (new 文本(st.nextElement () .toString ()),, new MyGenericWritable (new LongWritable (1)));
,,}
,,}
,}
,
,public static class Map2 extends Mapper<文本,文本,文本,MyGenericWritable>, {
public 才能;void 地图(Text 关键,Text 价值,Context 上下文),throws IOException, InterruptedException {
,,context.write(关键,new MyGenericWritable (new 文本(“1“)));
,,context.write(价值,new MyGenericWritable (new 文本(“1“)));
,,}
,}
,
,public static class Reduce extends Reducer<文本,MyGenericWritable,,文本,IntWritable>, {
public 才能;void 减少(Text 关键,Iterable,价值观,Context 上下文),throws IOException, InterruptedException {
,,int count =, 0;
,,Iteratorhadoop中如何实现GenericWritable
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