【MapReduce】MapReduce(DataJoin)實現數據連接+Bloom Filter優化

• 數據：
  file1：categoryname addressID

Beijing Red Star 1
Shenzhen Thunder 3
Guangzhou Honda 2
Beijing Rising 1
Guangzhou Development Bank 2
Tencent 3
Bank of Beijing 1
Nanchang Univ 5
Beijing Red Star 1
Nanchang Univ 5
Beijing Red Star 5
Shenzhen Thunder 6
Guangzhou Honda 5
Beijing Rising 6
Guangzhou Development Bank 3
Tencent 5
Bank of Beijing 6
Nanchang Univ 7
Beijing Red Star 1
Shenzhen Thunder 354
Guangzhou Honda 2
Beijing Rising 1
Guangzhou Development Bank 2
Tencent 334
Bank of Beijing 33
Nanchang Univ 5
Beijing Red Star 1
Nanchang Univ 5
Beijing Red Star 51
Shenzhen Thunder 6
Guangzhou Honda 52
Beijing Rising 66
Guangzhou Development Bank 3
Tencent 5
Bank of Beijing 6
Nanchang Univ 7
Beijing Red Star 1
Shenzhen Thunder 3
Guangzhou Honda 2
Beijing Rising 1
Guangzhou Development Bank 2
Tencent 3
Bank of Beijing 1
Nanchang Univ 5
Beijing Red Star 1
Nanchang Univ 5
Beijing Red Star 5
Shenzhen Thunder 8
Guangzhou Honda 5
Beijing Rising 27
Guangzhou Development Bank 3
Tencent 5
Bank of Beijing 9
Nanchang Univ 7
Beijing Red Star 1
Shenzhen Thunder 3
Guangzhou Honda 2
Beijing Rising 1
Guangzhou Development Bank 2
Tencent 3
Bank of Beijing 11
Nanchang Univ 5
Beijing Red Star 3
Nanchang Univ 5
Beijing Red Star 5
Shenzhen Thunder 6
Guangzhou Honda 5
Beijing Rising 6
Guangzhou Development Bank 3
Tencent 5
Bank of Beijing 6
Nanchang Univ 7
Beijing Red Star 1
Shenzhen Thunder 3
Guangzhou Honda 2
Beijing Rising 1
Guangzhou Development Bank 2
Tencent 3
Bank of Beijing 1
Nanchang Univ 5
Beijing Red Star 1
Nanchang Univ 5
Beijing Red Star 23
Shenzhen Thunder 6
Guangzhou Honda 5
Beijing Rising 6
Guangzhou Development Bank 3
Tencent 5
Bank of Beijing 6
Nanchang Univ 7

file2：addressID cityname

1 Beijing
2 Guangzhou
3 Shenzhen
4 Xian
5 xiamen
6 nanchang
7 sichuan
10 xinjiang
12 shanrao
23 heze
111 fuyang

輸出格式：
categoryname addressID cityname
例如：

factoryname addressID addressname
Beijing Red Star 1 Beijing
Beijing Red Star 1 Beijing
Bank of Beijing 1 Beijing
Beijing Rising 1 Beijing
Beijing Red Star 1 Beijing
Beijing Rising 1 Beijing
Beijing Red Star 1 Beijing
Beijing Red Star 1 Beijing
Bank of Beijing 1 Beijing

• 實現：
  比較複雜的實現代碼見：此處
  注意這裏實現的連接是內連接。
  Bloom Filter的完整實例化代碼可以寫成：

     public static int getOptimalBloomFilterSize(int numRecords, float falsePosRate) {
        int size = (int) (-numRecords * (float) Math.log(falsePosRate) / Math
                .pow(Math.log(2), 2));
        return size;
    }
    
    public static int getOptimalK(float numMembers, float vectorSize) {
        return (int) Math.round(vectorSize / numMembers * Math.log(2));
    }
    
 int numMembers = Integer.parseInt("10000");

 float falsePosRate = Float.parseFloat("0.01");
 
 int vectorSize = getOptimalBloomFilterSize(numMembers, falsePosRate);
 
 int nbHash = getOptimalK(numMembers, vectorSize);

 BloomFilter filter = new BloomFilter(vectorSize, nbHash, Hash.MURMUR_HASH);
 

也可以一句話實現：

static private BloomFilter filter1 = new BloomFilter(13287713, 9, MURMUR_HASH);

基本思路是先處理處兩個表中共有的addressID，存儲filter中，在對兩個表進行map的時候過濾掉addressID不在filter中的記錄。
可以將filter的內容寫入文件存到HDFS，然後從HDFS中讀入內容進行判斷（實現代碼可以參考👆鏈接中的博客）。這裏我直接使用了本地生成的filter。

實現代碼：

package com.company;


import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.filecache.DistributedCache;
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 static org.apache.hadoop.util.hash.Hash.MURMUR_HASH;
import org.apache.hadoop.util.bloom.BloomFilter;
import org.apache.hadoop.util.bloom.Key;


import javax.security.auth.kerberos.KerberosTicket;
import java.io.*;
import java.util.ArrayList;

public class Sy83 {

    static private BloomFilter filter1 = new BloomFilter(13287713, 9, MURMUR_HASH);
    static private BloomFilter filter = new BloomFilter(13287713, 9, MURMUR_HASH);


    public static class MapLeft extends Mapper<LongWritable, Text, Text, Text>{
        @Override
        public void map(LongWritable key, Text value, Mapper.Context context) throws IOException, InterruptedException {

            String line = value.toString();
            System.out.println(line);
            String[] keyValue = line.split(" ");
            //System.out.println(keyValue.length);
            if(keyValue.length<2) return ;
            String actoryname = "L", addressID = keyValue[keyValue.length-1];
            if(!filter.membershipTest(new Key(addressID.getBytes()))) {
                System.out.println("not:"+addressID);
                return ;
            }
            for(int i = 0; i < keyValue.length-1; i++) {
                if(i!=0) actoryname += " ";
                actoryname += keyValue[i];
            }

            System.out.println(addressID + " " + actoryname);

            context.write(new Text(addressID), new Text(actoryname));
        }
    }

    public static class MapRight extends Mapper<Object, Text, Text, Text>{

        public void map(Object key, Text value, Mapper.Context context) throws IOException, InterruptedException {

            String line = value.toString();
            System.out.println("xx"+line);
            String[] keyValue = line.split(" ");
            if(keyValue.length<2) return ;
            String addressname = "R", addressID = keyValue[0];
            for(int i = 1; i < keyValue.length; i++) {
                if(i>1) addressname += " ";
                addressname += keyValue[i];
            }
            if(!filter.membershipTest(new Key(addressID.getBytes()))) {
                System.out.println("not:"+addressID);
                return ;
            }
            System.out.println(addressID + " " + addressname);

            context.write(new Text(addressID), new Text(addressname));
        }
    }

    public static class ReduceTable extends Reducer<Text, Text, Text, Text> {

        boolean flag = false;
        public void reduce(Text key, Iterable<Text> values, Context context) throws
                IOException, InterruptedException {
            if(!flag) {
                context.write(new Text("factoryname  addressID"), new Text(" addressname"));
                flag = true;
            }
            ArrayList<Text> left = new ArrayList<Text>();
            ArrayList<Text> right = new ArrayList<Text>();
            try{
                for (Text value : values) {
                    String v = value.toString();
                    //System.out.println(v.substring(1, v.length()));
                    if(value.charAt(0)=='L') left.add(new Text(v.substring(1, v.length())));
                    else right.add(new Text(v.substring(1, v.length())));
                }
            }catch (Exception e){  e.printStackTrace();}
            System.out.println();
            if(left.size()==0 || right.size()==0) return ;
            for(Text L : left)
                for(Text R: right)
                    context.write(new Text(L+" "+key), new Text(" "+R));
        }
    }

    public static void main(String[] args) throws Exception {

        long startTime=System.nanoTime();   //獲取開始時間

        Job job = new Job(new Configuration(), "Jion table");
        JobConf conf=new JobConf(Sy83.class);
        FileSystem fs=FileSystem.get(conf);

        String in1 = "testdata/lab8/myfiles/file1";
        String in2 = "testdata/lab8/myfiles/file2";
        //String out = "testdata/lab8/out1"+ System.currentTimeMillis();

        String out = "testdata/lab8/outx";
        if(fs.exists(new Path(out))){
            fs.delete(new Path(out), true);
            System.out.println("存在此輸出路徑，已刪除！！！");
        }


        FSDataInputStream In1  = fs.open(new Path(in1));
        FSDataInputStream In2  = fs.open(new Path(in2));
        BufferedReader br1 = new BufferedReader(new InputStreamReader(In1));
        BufferedReader br2 = new BufferedReader(new InputStreamReader(In2));
        String line;
        while ((line = br2.readLine()) != null) {
            //System.out.println(line + " " + line.getBytes().length);
            if(line.getBytes().length==0) break ;
            String[] parts = line.split(" ");
            String addressID = parts[0];
            if(!filter1.membershipTest(new Key(addressID.getBytes())))
                filter1.add(new Key(addressID.getBytes()));
        }
        while ((line = br1.readLine()) != null) {
            //System.out.println(line + " " + line.getBytes().length);
            if(line.getBytes().length==0) break ;
            String[] parts = line.split(" ");
            String addressID = parts[parts.length-1];
            if(filter1.membershipTest(new Key(addressID.getBytes())))
                filter.add(new Key(addressID.getBytes()));
        }
        br1.close(); br2.close();

        System.out.println("filter already!");


        job.setJarByClass(Sy81.class);

        MultipleInputs.addInputPath(job, new Path(in1), TextInputFormat.class, MapLeft.class);
        MultipleInputs.addInputPath(job, new Path(in2), TextInputFormat.class, MapRight.class);

        job.setReducerClass(ReduceTable.class);

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

        FileOutputFormat.setOutputPath(job, new Path(out));

        if(job.waitForCompletion(true)){
            long endTime=System.nanoTime(); //獲取結束時間
            System.out.println("程序運行時間： "+(endTime-startTime)+"ns");
            System.exit(0);
        }else System.exit(1);

        System.exit(job.waitForCompletion(true) ? 0 : 1);

    }

}

• 結果截圖（部分）：