hadoop File statistics - Java Big Data

Java examples for Big Data:Hadoop

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Description

hadoop File statistics

Demo Code


import java.io.*;
import java.util.HashSet;

import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.util.GenericOptionsParser;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

public class Filestatistic {
    static int inloop = 0;
    static int outloop = 1;

    public static class fileMap extends Mapper<Object, Text, Text, Text> {
        private Text documentId;
        private Text word = new Text();

        @Override/*from  w w w  .j  a va 2s  .  c  om*/
        protected void setup(Context context) {
            String filename = ((FileSplit) context.getInputSplit())
                    .getPath().getName();
            documentId = new Text(filename);
        }

        @Override
        protected void map(Object key, Text value, Context context)
                throws IOException, InterruptedException {
            String[] words = value.toString().split(" ");
            for (String val : words) {
                word.set(val);
                context.write(word, documentId);
            }
        }
    }

    public static class fileReducer extends Reducer<Text, Text, Text, Text> {
        private Text docIds = new Text();

        @Override
        protected void reduce(Text key, Iterable<Text> values,
                Context context) throws IOException, InterruptedException {
            HashSet<Text> uniqueDocIds = new HashSet<Text>();
            for (Text val : values) {
                uniqueDocIds.add(val);
            }
            docIds.set(new Text(StringUtils.join(uniqueDocIds, ",")));
            context.write(key, docIds);
        }
    }

    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: numbersum <in> <out>");
            System.exit(2);
        }
        Job job = new Job(conf, "reverse Index");
        job.setJarByClass(Filestatistic.class);
        job.setMapperClass(fileMap.class);
        job.setReducerClass(fileReducer.class);
        job.setMapOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);

        Path inputPath = new Path(otherArgs[0]);
        Path outputPath = new Path(otherArgs[1]);
        FileInputFormat.addInputPath(job, inputPath);
        FileOutputFormat.setOutputPath(job, outputPath);
        Path deletePath = new Path(otherArgs[1] + "/_SUCCESS");
        outputPath.getFileSystem(conf).delete(deletePath, true);
        System.exit(job.waitForCompletion(true) ? 0 : 1);
        System.out.println("ok");

    }

}

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