Hadoop.2.x_WordCount本地测试示例

代码如下, 后备参考：

package com.bigdata.hadoop.hdfs;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
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;

public class WordCountTest {

	//step 1 Mapper Class
	public static class WordCountMapper extends Mapper<LongWritable, Text, Text, IntWritable>{

		private Text mapOutPutKey = new Text();
		private final static IntWritable mapOutPutValue = new IntWritable(1);
		@Override
		public void map(LongWritable key, Text value, Context context)
				throws IOException, InterruptedException {
			//get lines value
			String lineValue = value.toString();
			String[] strs = lineValue.split(" ");
			for(String str : strs){
				mapOutPutKey.set(str);
				context.write(mapOutPutKey, mapOutPutValue);
			}
		}
	}

	//step 2 Reducer Class
	public static class WordCountReducer extends Reducer<Text, IntWritable, Text, IntWritable>{

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

			//temp : sum
			int sum = 0;
			for(IntWritable value : values){
				sum += value.get();
			}
			outPutVlaue.set(sum);
			context.write(key, outPutVlaue);
		}
	}

	//step 3 Driver
	public int run(String[] args) throws Exception, InterruptedException{

		//get configuration
		Configuration configuration = new Configuration();
		//get a job
		Job job = Job.getInstance(configuration,this.getClass().getName());
		job.setJarByClass(getClass());
		//get a input path
		Path inPath = new Path(args[0]);
		FileInputFormat.addInputPath(job, inPath);
		//get a output path
		Path outPath = new Path(args[1]);
		FileOutputFormat.setOutputPath(job, outPath);

		//Mapper
		job.setMapperClass(WordCountMapper.class);
		job.setMapOutputKeyClass(Text.class);
		job.setOutputValueClass(IntWritable.class);

		//Reducer
		job.setReducerClass(WordCountReducer.class);
		job.setOutputKeyClass(Text.class);
		job.setOutputValueClass(IntWritable.class);

		//submit job
		boolean isSUccess = job.waitForCompletion(true);

		return isSUccess ? 0 : 1;
	}

	public static void main(String[] args) throws Exception {

		args = new String[]{
			"hdfs://linux-66-64.liuwl.com:8020/user/liuwl/tmp/input",
			"hdfs://linux-66-64.liuwl.com:8020/user/liuwl/tmp/output"
		};
		int status = new WordCountTest().run(args);

		System.exit(status);
	}
}