Hadoop demo 找出共同好友

需求

以下是qq的好友列表数据，冒号前是一个用，冒号后是该用户的所有好友（数据中的好友关系是单向的）

A:B,C,D,F,E,O

B:A,C,E,K

C:F,A,D,I

D:A,E,F,L

E:B,C,D,M,L

F:A,B,C,D,E,O,M

G:A,C,D,E,F

H:A,C,D,E,O

I:A,O

J:B,O

K:A,C,D

L:D,E,F

M:E,F,G

O:A,H,I,J

 

求出哪些人两两之间有共同好友，及他俩的共同好友都有谁？

第一步  

map

读一行   A:B,C,D,F,E,O

输出    <B,A><C,A><D,A><F,A><E,A><O,A>

在读一行   B:A,C,E,K

输出   <A,B><C,B><E,B><K,B>

 

 

REDUCE

拿到的数据比如<C,A><C,B><C,E><C,F><C,G>......

输出：  

<A-B,C>

<A-E,C>

<A-F,C>

<A-G,C>

<B-E,C>

<B-F,C>.....

 

 

 

第二步

map

读入一行<A-B,C>

直接输出<A-B,C>

 

reduce

读入数据  <A-B,C><A-B,F><A-B,G>.......

输出： A-B  C,F,G,.....

第一步

package com.asin.hdp.commfriend;import java.io.IOException;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.LongWritable;import org.apache.hadoop.io.Text;import org.apache.hadoop.mapreduce.Job;import org.apache.hadoop.mapreduce.Mapper;import org.apache.hadoop.mapreduce.Reducer;import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;public class CommFriendDemo {public static void main(String[] args) throws Exception {Configuration conf = new Configuration();Job job = Job.getInstance(conf);job.setJarByClass(CommFriendDemo.class);job.setMapperClass(CommFriendMapper.class);job.setReducerClass(CommFriendReduce.class);job.setOutputKeyClass(Text.class);job.setOutputValueClass(Text.class);FileInputFormat.addInputPath(job, new Path("F:/friend.txt"));FileOutputFormat.setOutputPath(job, new Path("F:/outputFriend1"));System.exit(job.waitForCompletion(true) ? 0 : 1);}}class CommFriendMapper extends Mapper<LongWritable, Text, Text, Text> {@Overrideprotected void map(LongWritable key, Text value, Mapper<LongWritable, Text, Text, Text>.Context context)throws IOException, InterruptedException {String line = value.toString();String[] split = line.split(":");String user = split[0];String[] friends = split[1].split(",");for (String friend : friends) {context.write(new Text(friend), new Text(user));}}}class CommFriendReduce extends Reducer<Text, Text, Text, Text> {@Overrideprotected void reduce(Text key, Iterable<Text> value, Reducer<Text, Text, Text, Text>.Context context)throws IOException, InterruptedException {String users = "";for (Text text : value) {users += text + ",";}context.write(key, new Text(users));}}

部分结果

AI,K,C,B,G,F,H,O,D,BA,F,J,E,CA,E,B,H,F,G,K,DG,C,K,A,L,F,E,H,EG,M,L,H,A,F,B,D,FL,M,D,C,G,A,

第二步

package com.asin.hdp.commfriend;import java.io.IOException;import java.util.Arrays;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.Path;import org.apache.hadoop.hbase.util.IterableUtils;import org.apache.hadoop.io.LongWritable;import org.apache.hadoop.io.Text;import org.apache.hadoop.mapreduce.Job;import org.apache.hadoop.mapreduce.Mapper;import org.apache.hadoop.mapreduce.Reducer;import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;public class CommFriendDemo2 {public static void main(String[] args) throws Exception {Configuration conf = new Configuration();Job job = Job.getInstance(conf);job.setJarByClass(CommFriendDemo2.class);job.setMapperClass(CommFriendMapperS.class);job.setReducerClass(CommFriendReduceS.class);job.setOutputKeyClass(Text.class);job.setOutputValueClass(Text.class);FileInputFormat.addInputPath(job, new Path("F:/outputFriend1/part-r-00000"));FileOutputFormat.setOutputPath(job, new Path("F:/outputFriend2"));System.exit(job.waitForCompletion(true) ? 0 : 1);}}class CommFriendMapperS extends Mapper<LongWritable, Text, Text, Text> {@Overrideprotected void map(LongWritable key, Text value, Mapper<LongWritable, Text, Text, Text>.Context context)throws IOException, InterruptedException {String line = value.toString();String[] split = line.split("\t");String friend = split[0];String users = split[1];String[] userArr = users.split(",");Arrays.sort(userArr);for (int i = 0; i < userArr.length - 2; i++) {for (int j = i + 1; j < userArr.length - 1; j++) {String user_user = userArr[i] + "-" + userArr[j];context.write(new Text(user_user), new Text(friend));}}}}class CommFriendReduceS extends Reducer<Text, Text, Text, Text> {@Overrideprotected void reduce(Text key, Iterable<Text> value, Reducer<Text, Text, Text, Text>.Context context)throws IOException, InterruptedException {String user = "";for (Text text : value) {user += text + ",";}context.write(key, new Text(user));}}

部分结果

A-BC,E,A-CF,D,A-DE,F,A-EB,C,D,A-FC,D,B,E,O,A-GD,E,F,C,