hadoop编程：分析CSDN注冊邮箱分布情况

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https://blog.csdn.net/jdh99/article/details/37565825

hadoop编程：分析CSDN注冊邮箱分布情况

本文博客链接:http://blog.csdn.net/jdh99,作者:jdh,转载请注明.

环境：

主机:Ubuntu10.04

hadoop版本号:1.2.1

开发工具:eclipse4.4.0

说明:

要求：原始数据共6428632条。分析不同邮箱的注冊情况，并按使用人数从大到小排序。

分析：hadoop自带一个排序，是按key值来进行排序的。要按值（value）进行排序，须要二次排序。

步骤：

1.job1：统计不同注冊邮箱的使用人数，用默认的key值排序，保存在HDFS系统中

2.job2：对job1的输出进行二次排序，按值从大到小排序

结果输出:

使用人数在1W以上的邮箱共同拥有24个：

qq.com    1976196
163.com    1766927
126.com    807895
sina.com    351596
yahoo.com.cn    205491
hotmail.com    202948
gmail.com    186843
sohu.com    104736
yahoo.cn    87048
tom.com    72365
yeah.net    53295
21cn.com    50710
vip.qq.com    35119
139.com    29207
263.net    24779
sina.com.cn    19156
live.cn    18920
sina.cn    18601
yahoo.com    18454
foxmail.com    16432
163.net    15176
msn.com    14211
eyou.com    13372
yahoo.com.tw    10810

源码:

JOB1：统计不同注冊邮箱的人数

CsdnData.java

package com.bazhangkeji.hadoop;
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.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;

public class CsdnData
{
	public static void main(String[] args) throws Exception
	{
		Configuration conf = new Configuration();
		String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
		if (otherArgs.length != 2)
		{
			System.err.println("Usage: csdndata <in> <out>");
			System.exit(2);
		}
		Job job = new Job(conf, "csdndata");

		job.setJarByClass(CsdnData.class);
		job.setMapperClass(MapData.class);

		job.setReducerClass(ReducerData.class);
		job.setOutputKeyClass(Text.class);

		job.setOutputValueClass(IntWritable.class);
		FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
		FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
		System.exit(job.waitForCompletion(true) ? 0 : 1);
  	}
}

MapData.java

package com.bazhangkeji.hadoop;
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;
import org.apache.hadoop.mapreduce.Mapper.Context;

public class MapData extends Mapper<Object, Text, Text, IntWritable>
{
	IntWritable one = new IntWritable(1);
  	Text word = new Text();

  	public void map(Object key, Text value, Context context) throws IOException, InterruptedException
	{
  		StringBuffer str_in = new StringBuffer();
		StringBuffer str_out = new StringBuffer();
		int index = 0;

		//初始化字符串
		str_in.setLength(0);
		str_out.setLength(0);
		str_in.append(value.toString());

		//获得邮箱的起始位置
		index = str_in.toString().lastIndexOf('@');
		if (index != -1)
		{
			word.set(str_in.toString().substring(index + 1).trim().toLowerCase());
  			context.write(word, one);
		}
  	}
}

ReducerData.java

package com.bazhangkeji.hadoop;
import java.io.IOException;

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

public class ReducerData extends Reducer<Text,IntWritable,Text,IntWritable>
{
	IntWritable result = new IntWritable();

  	public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException
	{
    	int sum = 0;
    	for (IntWritable val : values)
		{
      		sum += val.get();
    	}
    	result.set(sum);
    	context.write(key, result);
  	}
}

JOB2：对job1的输出进行二次排序。按值从大到小排序

SortSecond.java

package com.bazhangkeji.hadoop2;
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.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;

public class SortSecond
{
	public static void main(String[] args) throws Exception
	{
		Configuration conf = new Configuration();
		String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
		if (otherArgs.length != 2)
		{
			System.err.println("Usage: csdndata <in> <out>");
			System.exit(2);
		}
		Job job = new Job(conf, "sortsecond");
		job.setJarByClass(SortSecond.class);

		job.setMapperClass(MapSecond.class);
		job.setReducerClass(ReduceSecond.class); 

		job.setSortComparatorClass(SortMy.class); //设置自己定义二次排序策略

		job.setOutputKeyClass(KeyMy.class);
		job.setOutputValueClass(IntWritable.class);

		FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
		FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
		System.exit(job.waitForCompletion(true) ?

0 : 1);
  	}
}

MapSecond.java

package com.bazhangkeji.hadoop2;
import java.io.IOException;
import java.util.StringTokenizer;

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

public class MapSecond extends Mapper<LongWritable, Text, KeyMy, IntWritable>
{
	IntWritable one = new IntWritable(1);
  	Text word = new Text();
  	KeyMy keymy = new KeyMy();

  	public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException
	{
  		String str_in = value.toString();
  		int index = 0;

  		index = str_in.indexOf('\t');
  		if (value.toString().length() > 3 && index != -1)
  		{
	  		String str1 = str_in.substring(0, index);
	  		String str2 = str_in.substring(index + 1);

	  		if (str1.length() != 0 && str2.length() != 0)
	  		{
	  			one.set(Integer.parseInt(str2));
	  			word.set(str1);
				keymy.setFirstKey(word);
				keymy.setSecondKey(one);
	  			context.write(keymy, one);
	  		}
  		}
  	}
}

ReduceSecond.java

package com.bazhangkeji.hadoop2;
import java.io.IOException;

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

public class ReduceSecond extends Reducer<KeyMy,IntWritable,Text,IntWritable>
{
	IntWritable result = new IntWritable();

  	public void reduce(KeyMy key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException
	{
    	context.write(key.getFirstKey(), key.getSecondKey());
  	}
}

KeyMy.java

package com.bazhangkeji.hadoop2;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.WritableComparable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
 * 自己定义组合键
 */
public class KeyMy implements WritableComparable<KeyMy>{
    private static final Logger logger = LoggerFactory.getLogger(KeyMy.class);
    private Text firstKey;
    private IntWritable secondKey;
    public KeyMy() {
        this.firstKey = new Text();
        this.secondKey = new IntWritable();
    }
    public Text getFirstKey() {
        return this.firstKey;
    }
    public void setFirstKey(Text firstKey) {
        this.firstKey = firstKey;
    }
    public IntWritable getSecondKey() {
        return this.secondKey;
    }
    public void setSecondKey(IntWritable secondKey) {
        this.secondKey = secondKey;
    }
    @Override
    public void readFields(DataInput dateInput) throws IOException {
        // TODO Auto-generated method stub
        this.firstKey.readFields(dateInput);
        this.secondKey.readFields(dateInput);
    }
    @Override
    public void write(DataOutput outPut) throws IOException {
        this.firstKey.write(outPut);
        this.secondKey.write(outPut);
    }
    /**
     * 自己定义比較策略
     * 注意：该比較策略用于 mapreduce的第一次默认排序，也就是发生在map阶段的sort小阶段，
     * 发生地点为环形缓冲区(能够通过io.sort.mb进行大小调整)
     */
    @Override
    public int compareTo(KeyMy KeyMy) {
        logger.info("-------KeyMy flag-------");
        return this.firstKey.compareTo(KeyMy.getFirstKey());
    }
}

SortMy.java

package com.bazhangkeji.hadoop2;

import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableComparator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
 * 自己定义二次排序策略
 */
public class SortMy extends WritableComparator {
    private static final Logger logger = LoggerFactory.getLogger(SortMy.class);
    public SortMy() {
        super(KeyMy.class,true);
    }
    @Override
    public int compare(WritableComparable KeyMyOne,
            WritableComparable KeyMyOther)
    {
        logger.info("---------enter SortMy flag---------");

        KeyMy c1 = (KeyMy) KeyMyOne;
        KeyMy c2 = (KeyMy) KeyMyOther;

        return c2.getSecondKey().get()-c1.getSecondKey().get();//0,负数,正数
    }
}

參考资料:

1.《hadoop权威指南》

2.  http://zengzhaozheng.blog.51cto.com/8219051/1379271