IDEA手写WritableComparable排序案例实操

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需求：对序列化案例中产生的文件再进行一次按照总流量倒序输出。

利用框架在MapTask结束后必然要对Key排序的特点，对总流量进行排序

FlowBean类，实现WritableComparable接口(框架实现多态的比较接口)

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package com.atguigu.writablecomparable;


import org.apache.hadoop.io.WritableComparable;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

public class FlowBean implements WritableComparable<FlowBean> {
    private long upFlow;
    private long downFlow;
    private long sumFlow;

    public FlowBean() {//反射需要提供无参构造方法
    }

    @Override
    public String toString() {
        return upFlow + "\t" + downFlow + "\t" + sumFlow;
    }

    public void set(long upFlow,long downFlow){
        this.upFlow = upFlow;
        this.downFlow = downFlow;
        this.sumFlow = upFlow + downFlow;
    }

    public long getUpFlow() {
        return upFlow;
    }

    public void setUpFlow(long upFlow) {
        this.upFlow = upFlow;
    }

    public long getDownFlow() {
        return downFlow;
    }

    public void setDownFlow(long downFlow) {
        this.downFlow = downFlow;
    }

    public long getSumFlow() {
        return sumFlow;
    }

    public void setSumFlow(long sumFlow) {
        this.sumFlow = sumFlow;
    }

    /**
     * 序列化方法
     * @param dataOutput：框架提供的数据出口
     * @throws IOException
     */
    public void write(DataOutput dataOutput) throws IOException {
        //顺序和反序列化的顺序要一模一样
        dataOutput.writeLong(upFlow);
        dataOutput.writeLong(downFlow);
        dataOutput.writeLong(sumFlow);
    }

    /**
     * 反序列化方法
     * @param dataInput：框架提供的数据来源
     * @throws IOException
     */
    public void readFields(DataInput dataInput) throws IOException {
        //顺序和序列化的顺序要一模一样
        upFlow = dataInput.readLong();
        downFlow = dataInput.readLong();
        sumFlow = dataInput.readLong();
    }

    @Override
    public int compareTo(FlowBean o) {//按照总流量降序排列
        return Long.compare(o.sumFlow,this.sumFlow);
    }
}

SortMapper类：
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package com.atguigu.writablecomparable;

import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;

import java.io.IOException;

public class SortMapper extends Mapper<LongWritable, Text,FlowBean,Text> {

    private FlowBean flow = new FlowBean();
    private Text phone = new Text();

    @Override
    protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
        String[] fields = value.toString().split("\t");
        phone.set(fields[0]);
        flow.setUpFlow(Long.parseLong(fields[1]));
        flow.setDownFlow(Long.parseLong(fields[2]));
        flow.setSumFlow(Long.parseLong(fields[3]));

        context.write(flow,phone);
    }
}

SortReducer类：
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package com.atguigu.writablecomparable;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;


import java.io.IOException;

public class SortReducer extends Reducer<FlowBean, Text, Text,FlowBean> {

    @Override
    protected void reduce(FlowBean key, Iterable<Text> values, Context context) throws IOException, InterruptedException {
        for (Text value : values) {
            context.write(value,key);
        }
    }
}

SortDriver类：
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package com.atguigu.writablecomparable;

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 SortDriver {
    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
        Job job = Job.getInstance(new Configuration());

        job.setJarByClass(SortDriver.class);
        job.setMapperClass(SortMapper.class);
        job.setReducerClass(SortReducer.class);

        job.setMapOutputKeyClass(FlowBean.class);
        job.setMapOutputValueClass(Text.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(FlowBean.class);

        FileInputFormat.setInputPaths(job, new Path("F:/output"));
        FileOutputFormat.setOutputPath(job, new Path("F:/output2"));

        boolean b = job.waitForCompletion(true);
        System.exit(b ? 0 : 1);
    }
}

需求：在前一个需求的基础上，增加自定义分区类，分区按照省份手机号设置

MyPartitioner2类：

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package com.atguigu.writablecomparable2;

import com.atguigu.writablecomparable.FlowBean;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Partitioner;


public class MyPartitioner2 extends Partitioner<FlowBean, Text> {
    @Override
    public int getPartition(FlowBean flowBean, Text text, int i) {
        switch (text.toString().substring(0, 3)) {
            case "136":
                return 0;
            case "137":
                return 1;
            case "138":
                return 2;
            case "139":
                return 3;
            default:
                return 4;

        }
    }
}

SortDriver类：
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package com.atguigu.writablecomparable2;

import com.atguigu.writablecomparable.FlowBean;
import com.atguigu.writablecomparable.SortMapper;
import com.atguigu.writablecomparable.SortReducer;
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 SortDriver {
    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
        Job job = Job.getInstance(new Configuration());

        job.setJarByClass(SortDriver.class);
        job.setMapperClass(SortMapper.class);
        job.setReducerClass(SortReducer.class);

        job.setMapOutputKeyClass(FlowBean.class);
        job.setMapOutputValueClass(Text.class);

        job.setPartitionerClass(MyPartitioner2.class);
        job.setNumReduceTasks(5);

        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(FlowBean.class);

        FileInputFormat.setInputPaths(job, new Path("F:/output"));
        FileOutputFormat.setOutputPath(job, new Path("F:/output2"));

        boolean b = job.waitForCompletion(true);
        System.exit(b ? 0 : 1);
    }
}

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