| /** |
| * 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 org.apache.hadoop.examples; |
| |
| import java.io.IOException; |
| import java.util.StringTokenizer; |
| |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.io.IntWritable; |
| 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.GenericOptionsParser; |
| |
| public class WordCount { |
| |
| public static class TokenizerMapper |
| extends Mapper<Object, Text, Text, IntWritable>{ |
| |
| private final static IntWritable one = new IntWritable(1); |
| private Text word = new Text(); |
| |
| public void map(Object key, Text value, Context context |
| ) throws IOException, InterruptedException { |
| StringTokenizer itr = new StringTokenizer(value.toString()); |
| while (itr.hasMoreTokens()) { |
| word.set(itr.nextToken()); |
| context.write(word, one); |
| } |
| } |
| } |
| |
| public static class IntSumReducer |
| extends Reducer<Text,IntWritable,Text,IntWritable> { |
| private IntWritable result = new IntWritable(); |
| |
| public void reduce(Text key, Iterable<IntWritable> values, |
| Context context |
| ) throws IOException, InterruptedException { |
| int sum = 0; |
| for (IntWritable val : values) { |
| sum += val.get(); |
| } |
| result.set(sum); |
| context.write(key, result); |
| } |
| } |
| |
| 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: wordcount <in> [<in>...] <out>"); |
| System.exit(2); |
| } |
| Job job = Job.getInstance(conf, "word count"); |
| job.setJarByClass(WordCount.class); |
| job.setMapperClass(TokenizerMapper.class); |
| job.setCombinerClass(IntSumReducer.class); |
| job.setReducerClass(IntSumReducer.class); |
| job.setOutputKeyClass(Text.class); |
| job.setOutputValueClass(IntWritable.class); |
| for (int i = 0; i < otherArgs.length - 1; ++i) { |
| FileInputFormat.addInputPath(job, new Path(otherArgs[i])); |
| } |
| FileOutputFormat.setOutputPath(job, |
| new Path(otherArgs[otherArgs.length - 1])); |
| System.exit(job.waitForCompletion(true) ? 0 : 1); |
| } |
| } |