每日日报2021 9/21

我昨天在idea中用的那个依赖，所对应的代码，这直接粘贴过来了，不知道为啥，省略没了。

package com.atguigu.mapreduce.wordcount;

import java.io.IOException;

import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Mapper;

public class WordCountMapper extends Mapper<LongWritable, Text, Text,

IntWritable>{

Text k = new Text();

IntWritable v = new IntWritable(1);

@Override

protected void map(LongWritable key, Text value, Context context)

throws IOException, InterruptedException {

// 1 获取一行

String line = value.toString();

// 2 切割

String[] words = line.split(" ");

// 3 输出

for (String word : words) {

k.set(word);

context.write(k, v);

}

}

}

 

 

package com.atguigu.mapreduce.wordcount;

import java.io.IOException;

import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Reducer;

public class WordCountReducer extends Reducer<Text, IntWritable, Text,

IntWritable>{

int sum;

IntWritable v = new IntWritable();

@Override

protected void reduce(Text key, Iterable<IntWritable> values,Context

context) throws IOException, InterruptedException {

// 1 累加求和

sum = 0;

for (IntWritable count : values) {

sum += count.get();

}

// 2 输出

v.set(sum);

context.write(key,v);

}

}