package com.bsr.cross;

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;

/**

 * 第一次mr--目的是获取某一人是哪些人的好友

 *

 *

 */

public class Cross {

    //输入：A:B,C,D,F,E,O

    //输出：B->A C->A D->A F->A E->A O->A

    public static class Map extends Mapper<LongWritable, Text, Text, Text>{

        @Override

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

                throws IOException, InterruptedException {

            String[] value1=value.toString().split(":");

            String[] value2=value1[1].split(",");

            for (String string : value2) {

                context.write(new Text(string), new Text(value1[0]));

            }

        }

    }

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

        // 输入<B->A><B->E><B->F>....

        // 输出 B A,E,F,J

        @Override

        protected void reduce(Text key, Iterable<Text> value,Context context)

                throws IOException, InterruptedException {

            StringBuffer sb=new StringBuffer();

            for (Text text : value) {

                sb.append(text+",");

            }

            context.write(key, new Text(sb.toString()));

        }

    }

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

        //读取classpath下的所有xxx-site.xml配置文件，并进行解析

        Configuration conf=new Configuration();

        FileSystem fs = FileSystem.get(configuration);

        String s = "/wc/output3";

        Path path = new Path(s);

        fs.delete(path, true);

        Job job=Job.getInstance(conf);

        //通过主类的类加载器机制获取到本job的所有代码所在的jar包

        job.setJarByClass(Cross.class);

        //指定本job使用的mapper类

        job.setMapperClass(Map.class);

        //指定本job使用的reducer类

        job.setReducerClass(Reduce.class);

        //指定mapper输出的kv数据类型

        job.setMapOutputKeyClass(Text.class);

        job.setMapOutputValueClass(Text.class);

        //指定reducer输出的kv数据类型

        job.setOutputKeyClass(Text.class);

        job.setOutputValueClass(Text.class);

        //指定本job要处理的文件所在的路径

        FileInputFormat.setInputPaths(job, new Path("/wc/data/"));

        FileOutputFormat.setOutputPath(job, new Path("/wc/output3"));

        //将本job向hadoop集群提交执行

        boolean flag=job.waitForCompletion(true);

        System.exit(flag?0:1);

    }

    }