com.bigdog.hadoop.mapreduce.counter.WordCountCounterApp.java Source code

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Here is the source code for com.bigdog.hadoop.mapreduce.counter.WordCountCounterApp.java

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package com.bigdog.hadoop.mapreduce.counter;

import com.bigdog.hadoop.Constants;

import java.net.URI;

import org.apache.hadoop.conf.Configuration;
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.mapreduce.Counter;
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;

/**
 *
 * @author jw362j
 */
public class WordCountCounterApp {

    static final String INPUT_PATH = Constants.input;
    static final String OUT_PATH = Constants.output;

    static {
        Configuration.addDefaultResource("hdfs-site.xml");
        Configuration.addDefaultResource("core-site.xml");
        Configuration.addDefaultResource("mapred-site.xml");
    }

    public void CustomerCounter() throws Exception {
        Configuration conf = new Configuration();
        final FileSystem fileSystem = FileSystem.get(new URI(INPUT_PATH), conf);
        final Path outPath = new Path(OUT_PATH);
        if (fileSystem.exists(outPath)) {
            fileSystem.delete(outPath, true);
        }

        final Job job = new Job(conf, WordCountCounterApp.class.getSimpleName());
        //1.1??
        FileInputFormat.setInputPaths(job, INPUT_PATH);
        //????
        //job.setInputFormatClass(TextInputFormat.class);

        //1.2 map
        job.setMapperClass(MyMapper.class);
        //map<k,v><k3,v3><k2,v2>??
        //job.setMapOutputKeyClass(Text.class);
        //job.setMapOutputValueClass(LongWritable.class);

        //1.3 
        //job.setPartitionerClass(HashPartitioner.class);
        //reduce?
        //job.setNumReduceTasks(1);

        //1.4 TODO ??

        //1.5 TODO 

        //2.2 reduce
        job.setReducerClass(MyReducer.class);
        //reduce
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(LongWritable.class);

        //2.3 
        FileOutputFormat.setOutputPath(job, outPath);
        //?
        //job.setOutputFormatClass(TextOutputFormat.class);

        //job??JobTracker?
        job.waitForCompletion(true);
    }

    /**
    * KEYIN   ?k1      ???
    * VALUEIN   ?v1      
    * KEYOUT   ?k2      ??
    * VALUEOUT   ?v2      ??1
    */
    static class MyMapper extends Mapper<LongWritable, Text, Text, LongWritable> {
        protected void map(LongWritable k1, Text v1, Context context)
                throws java.io.IOException, InterruptedException {
            final Counter helloCounter = context.getCounter("Sensitive Words", "no");

            final String line = v1.toString();
            if (line.contains("no")) {
                //??
                helloCounter.increment(1L);
            }
            final String[] splited = line.split("\t");
            for (String word : splited) {
                context.write(new Text(word), new LongWritable(1));
            }
        };
    }

    /**
    * KEYIN   ?k2      ??
    * VALUEIN   ?v2      ??
    * KEYOUT   ?k3      ????
    * VALUEOUT   ?v3      ????
    *
    */

    static class MyReducer extends Reducer<Text, LongWritable, Text, LongWritable> {
        protected void reduce(Text k2, java.lang.Iterable<LongWritable> v2s, Context ctx)
                throws java.io.IOException, InterruptedException {
            long times = 0L;
            for (LongWritable count : v2s) {
                times += count.get();
            }
            ctx.write(k2, new LongWritable(times));
        };
    }

}