|
|
| Line 190: |
Line 190: |
| | [[Hadoop WordCount.java | WordCount.java]] | | [[Hadoop WordCount.java | WordCount.java]] |
| | | | |
| − | ===The Map and Reduce Java Blocks===
| |
| − |
| |
| − | <source lang="java">
| |
| − | public static class MapClass 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();
| |
| − | StringTokenizer itr = new StringTokenizer(line);
| |
| − | while (itr.hasMoreTokens()) {
| |
| − | word.set(itr.nextToken());
| |
| − | output.collect(word, one);
| |
| − | }
| |
| − | }
| |
| − | }
| |
| − |
| |
| − | /**
| |
| − | * A reducer class that just emits the sum of the input values.
| |
| − | */
| |
| − | 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));
| |
| − | }
| |
| − | }
| |
| − | </source>
| |
| | | | |
| | <br /> | | <br /> |
