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author | Patrick Simianer <p@simianer.de> | 2014-06-14 16:46:27 +0200 |
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committer | Patrick Simianer <p@simianer.de> | 2014-06-14 16:46:27 +0200 |
commit | 26c490f404731d053a6205719b6246502c07b449 (patch) | |
tree | 3aa721098f1251dfbf2249ecd2736434c13b1d48 /hadoop/wordcount/WordCount.java |
init
Diffstat (limited to 'hadoop/wordcount/WordCount.java')
-rw-r--r-- | hadoop/wordcount/WordCount.java | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/hadoop/wordcount/WordCount.java b/hadoop/wordcount/WordCount.java new file mode 100644 index 0000000..8917aee --- /dev/null +++ b/hadoop/wordcount/WordCount.java @@ -0,0 +1,57 @@ +package org.myorg; + +import java.io.IOException; +import java.util.*; + +import org.apache.hadoop.fs.Path; +import org.apache.hadoop.conf.*; +import org.apache.hadoop.io.*; +import org.apache.hadoop.mapred.*; +import org.apache.hadoop.util.*; + +public class WordCount { + + // Mapper + public static class Map extends MapReduceBase implements Mapper<LongWritable, Text, Text, IntWritable> { + private final static IntWritable one = new IntWritable(1); + private Text word = new Text(); + public void map(LongWritable key, Text value, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException { + String line = value.toString(); // TextInputFormat + StringTokenizer tokenizer = new StringTokenizer(line); + while (tokenizer.hasMoreTokens()) { + word.set(tokenizer.nextToken()); + output.collect(word, one); + } + } + } + + // Reducer + public static class Reduce extends MapReduceBase implements Reducer<Text, IntWritable, Text, IntWritable> { + public void reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException { + int sum = 0; + while (values.hasNext()) { + sum += values.next().get(); + } + output.collect(key, new IntWritable(sum)); + } + } + + // Driver + public static void main(String[] args) throws Exception { + JobConf conf = new JobConf(WordCount.class); + conf.setJobName("wordcount"); + conf.setNumReduceTasks(200); + conf.setOutputKeyClass(Text.class); + conf.setOutputValueClass(IntWritable.class); + conf.setMapperClass(Map.class); + conf.setCombinerClass(Reduce.class); // Combiner + conf.setReducerClass(Reduce.class); + conf.setInputFormat(TextInputFormat.class); + conf.setOutputFormat(TextOutputFormat.class); + FileInputFormat.setInputPaths(conf, new Path(args[0])); + FileOutputFormat.setOutputPath(conf, new Path(args[1])); + JobClient.runJob(conf); + } + +} + |