com.fanlehai.hadoop.serialize.avro.MapReduceColorCount.java Source code

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Here is the source code for com.fanlehai.hadoop.serialize.avro.MapReduceColorCount.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.fanlehai.hadoop.serialize.avro;

import java.io.IOException;

import org.apache.avro.Schema;
import org.apache.avro.mapred.AvroKey;
import org.apache.avro.mapred.AvroValue;
import org.apache.avro.mapreduce.AvroJob;
import org.apache.avro.mapreduce.AvroKeyInputFormat;
import org.apache.avro.mapreduce.AvroKeyValueOutputFormat;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.NullWritable;
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;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

/*
 * 1.?user.java
 * avrotool?user.avsc?User.javaavro?
 * java -jar /Users/liuhai/lib/AVRO/1.8.1/avro-tools-1.8.1.jar compile schema user.avsc .
 * 2.GenericReadWrite?users.avro
 * 3.users.avrohdfs
 * hdfs dfs -put users.avro .
 * 
 * 4.??
 * export LIBJARS=/Users/liuhai/lib/AVRO/1.8.1/avro-mapred-1.8.1.jar,/Users/liuhai/lib/AVRO/1.8.1/avro-1.8.1.jar
 * export HADOOP_CLASSPATH=$HADOOP_CLASSPATH:/Users/liuhai/lib/AVRO/1.8.1/avro-mapred-1.8.1.jar:/Users/liuhai/lib/AVRO/1.8.1/avro-1.8.1.jar
 * hadoop jar avro.jar serialize.avro.MapReduceColorCount -libjars $LIBJARS user.avro avrocolor
 * 
 */

public class MapReduceColorCount extends Configured implements Tool {

    public static class ColorCountMapper extends Mapper<AvroKey<User>, NullWritable, Text, IntWritable> {

        @Override
        public void map(AvroKey<User> key, NullWritable value, Context context)
                throws IOException, InterruptedException {

            CharSequence color = key.datum().getFavoriteColor();
            if (color == null) {
                color = "none";
            }
            context.write(new Text(color.toString()), new IntWritable(1));
        }
    }

    public static class ColorCountReducer
            extends Reducer<Text, IntWritable, AvroKey<CharSequence>, AvroValue<Integer>> {

        @Override
        public void reduce(Text key, Iterable<IntWritable> values, Context context)
                throws IOException, InterruptedException {

            int sum = 0;
            for (IntWritable value : values) {
                sum += value.get();
            }
            context.write(new AvroKey<CharSequence>(key.toString()), new AvroValue<Integer>(sum));
        }
    }

    public int run(String[] args) throws Exception {

        if (args.length != 2) {
            printUsage();
        }

        FileSystem.get(new Configuration()).delete(new Path(args[1]), true);
        Job job = Job.getInstance(super.getConf(), "MapReduceAvroWordCount");

        job.setJarByClass(MapReduceColorCount.class);
        job.setJobName("Color Count");

        FileInputFormat.setInputPaths(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));

        job.setInputFormatClass(AvroKeyInputFormat.class);
        job.setMapperClass(ColorCountMapper.class);
        AvroJob.setInputKeySchema(job, User.getClassSchema());
        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(IntWritable.class);

        job.setOutputFormatClass(AvroKeyValueOutputFormat.class);
        job.setReducerClass(ColorCountReducer.class);
        AvroJob.setOutputKeySchema(job, Schema.create(Schema.Type.STRING));
        AvroJob.setOutputValueSchema(job, Schema.create(Schema.Type.INT));

        return job.waitForCompletion(true) ? 1 : 0;
    }

    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();

        int res = ToolRunner.run(conf, new MapReduceColorCount(), args);
        if (res == 0) {
            System.err.println("something bad happened !");
        } else {
            System.out.println("MapReduceColorCount is done !");
        }

        System.exit(res);
    }

    private void printUsage() {
        System.err.println("Usage: MapReduceColorCount <in> <out>");
        ToolRunner.printGenericCommandUsage(System.err);
        System.exit(2);
    }
}