WordCount Partitioner

MapReduce

WordCountMr

package com.zc.hadoop.mapreduce.partition;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
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;
import org.apache.hadoop.util.Tool;
public class WordCountMr extends Configured implements Tool{
    public static void main(String[] args) throws Exception{
//      System.setProperty("hadoop.home.dir","E:\\zc\\大数据\\工具\\hadoop-2.5.0\\"); 
//      args = new String[]{ 
//               "/user/zc/tmp/input" ,
//               "/user/zc/tmp/output"+System.currentTimeMillis() };
        int status = new WordCountMr().run(args);
        System.exit(status);
    }
    // Map
    public static class WCMapper extends
            Mapper<LongWritable, Text, Text, IntWritable> {
        private Text mapOutPutkey = new Text();
        private final static IntWritable mapOutPutValue = new IntWritable(1);
        @Override
        protected void map(LongWritable key, Text value, Context context)
                throws IOException, InterruptedException {
            String linvalue = value.toString();
            String[] strs = linvalue.split(" ");
            for(String str:strs)
            {
                mapOutPutkey.set(str);
                context.write(mapOutPutkey, mapOutPutValue);
            }
        }
    }
    // Reduce
    public static class WCReduce extends
            Reducer<Text, IntWritable, Text, IntWritable> {
        private IntWritable outputvalue = new IntWritable();
        @Override
        public void reduce(Text key, Iterable<IntWritable> values,
                Context context) throws IOException, InterruptedException {
            int showsum = 0;
            for(IntWritable value:values){
                showsum += value.get();
            }
            outputvalue.set(showsum);
            context.write(key, outputvalue);
        }
    }
    /**
     * @param 
     * */
    // Driver
    public int run(String[] args) throws Exception {
        // 1 set configuration
        Configuration configuration = new Configuration();
        // 2 create job
        Job job = Job.getInstance(configuration, this.getClass()
                .getSimpleName());
        job.setJarByClass(this.getClass());
        // 3.1 set job
        Path path = new Path(args[0]);
        FileInputFormat.addInputPath(job, path);
        // 3.2 set mapper
        job.setMapperClass(WCMapper.class);
        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(IntWritable.class);
        //-----------Shuffle------分区--------------------
        //1)partitioner分区
        job.setPartitionerClass(WCPartitioner.class);
        //reduce task number
        job.setNumReduceTasks(3);
        //-----------------Shuffle--------------------
        // 3.3 set reduce
        job.setReducerClass(WCReduce.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);
        //3.4 set output
        Path outpPath = new Path(args[1]);
        FileOutputFormat.setOutputPath(job, outpPath);
        //submit
        boolean b = job.waitForCompletion(true);
        return b?0:1;
    }
}

WCPartitioner

package com.zc.hadoop.mapreduce.partition;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Partitioner;
public class WCPartitioner extends Partitioner<Text, IntWritable> {
    /** 
     * @ClassName: WCPartitioner  
     * @Description: 根据字母大小写分区，其他0，小写1，大写2（在此建立了3个分区，即会产生3个reduce任务输出到不同的文件0和1,2） 
     * @param K k2(map输出的键), V v2(map输出的值) 
     * @author zc
     */ 
    @Override
    public int getPartition(Text key, IntWritable value,
            int numPartitions) {
        if(null==key)
            return 0;
        String str = key.toString();
        if(str.matches("^[a-z]+$")){
			return 1;
		}
		if(str.matches("^[A-Z]+$")){
            return 2;
        }
        return 0;
    }
}

在此输入正文