每日日报2021 10/10

昨天两天写的都是读后感，但是呢，我的每日日报没有停下来，所以呢，今日把所有的都贴出来。

 

（2）编写 Mapper 类

package com.atguigu.mapreduce.writablecompable;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Mapper; 尚硅谷大数据技术之 Hadoop（MapReduce）

import java.io.IOException;

public class FlowMapper extends Mapper<LongWritable, Text, FlowBean, Text>

{

private FlowBean outK = new FlowBean();

private Text outV = new Text();

@Override

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

throws IOException, InterruptedException {

//1 获取一行数据

String line = value.toString();

//2 按照"\t",切割数据

String[] split = line.split("\t");

//3 封装 outK outV

outK.setUpFlow(Long.parseLong(split[1]));

outK.setDownFlow(Long.parseLong(split[2]));

outK.setSumFlow();

outV.set(split[0]);

//4 写出 outK outV

context.write(outK,outV);

}

}

（

3）编写 Reducer 类

package com.atguigu.mapreduce.writablecompable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Reducer;

import java.io.IOException;

public class FlowReducer extends Reducer<FlowBean, Text, Text, FlowBean>

{

@Override

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

context) throws IOException, InterruptedException {

//遍历 values 集合,循环写出,避免总流量相同的情况

for (Text value : values) {

//调换 KV 位置,反向写出

context.write(value,key);

}

}

}

（

4）编写 Driver 类

package com.atguigu.mapreduce.writablecompable;

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.lib.input.FileInputFormat;

import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import java.io.IOException;

public class FlowDriver { 尚硅谷大数据技术之 Hadoop（MapReduce

）

public static void main(String[] args) throws IOException,

ClassNotFoundException, InterruptedException {

//1 获取 job 对象

Configuration conf = new Configuration();

Job job = Job.getInstance(conf);

//2 关联本 Driver 类

job.setJarByClass(FlowDriver.class);

//3 关联 Mapper 和 Reducer

job.setMapperClass(FlowMapper.class);

job.setReducerClass(FlowReducer.class);

//4 设置 Map 端输出数据的 KV 类型

job.setMapOutputKeyClass(FlowBean.class);

job.setMapOutputValueClass(Text.class);

//5 设置程序最终输出的 KV 类型

job.setOutputKeyClass(Text.class);

job.setOutputValueClass(FlowBean.class);

//6 设置输入输出路径

FileInputFormat.setInputPaths(job, new Path("D:\\inputflow2"));

FileOutputFormat.setOutputPath(job, new Path("D:\\comparout"));

//7 提交 Job

boolean b = job.waitForCompletion(true);

System.exit(b ? 0 : 1);

}

}