Hadoop--08--WordCount

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<span style="font-family:SimSun;font-size:18px;">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 {  </span>

<span style="font-family:SimSun;font-size:18px;">
	<span style="white-space:pre">	</span>public static class WordCountMap 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 tokenizer = new StringTokenizer(line);  
			 while (tokenizer.hasMoreTokens()) {  
			   word.set(tokenizer.nextToken());  
			   output.collect(word, one);  
			 }  
			}  
		}  
	
		public static class WordCountReduce 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));  
			}  
		
		}  
		
		public static void main(String[] args) throws Exception {  
			JobConf conf = new JobConf(WordCount.class);  
			conf.setJobName("wordcount");  
			  
			conf.setOutputKeyClass(Text.class);  
			conf.setOutputValueClass(IntWritable.class);  
			  
			conf.setMapperClass(Map.class);  
			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);  
			}  
	}  </span>

Hadoop--08--WordCount

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原文地址：http://blog.csdn.net/baidu_21578557/article/details/52068806