hadoop程序MapReduce之DataSort

需求：对文件中的数据进行排序。

样本：sort.log

10

13

10

20

输出：1 10

2 10

3 13

4 20

分析部分：

mapper分析：

1、<k1,v1>k1代表：行位置编号，v1代表：一行数据

2、<k2,v2>k2代表：一行数据，v2代表：此处为1.

reduce分析：

3、<k3,v3>k3代表：相同的key,v3代表：list<int>

4、合并输出：<k4,v4>k4代表：递增编号，v4代表：key值。

程序部分：

SortMapper类：

package com.cn.sort;

import java.io.IOException;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;

public class SortMapper extends Mapper<Object, Text, IntWritable, IntWritable> {
    String line = null;
    @Override
    protected void map(Object key, Text value, Context context)
            throws IOException, InterruptedException {
         line = value.toString();
         int lineValue = Integer.parseInt(line);
         context.write(new IntWritable(lineValue), new IntWritable(1));
    }
}

SortReduce类

package com.cn.sort;

import java.io.IOException;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.mapreduce.Reducer;

public class SortReduce extends Reducer<IntWritable, IntWritable, IntWritable, IntWritable>{
    IntWritable lineNum = new IntWritable(1);
    @Override
    protected void reduce(IntWritable key, Iterable<IntWritable> values,Context context)
                    throws IOException, InterruptedException {
        for(IntWritable value : values){
            context.write(lineNum, key);
            lineNum = new IntWritable(lineNum.get()+1);
        }
    }
}

DataSort类

package com.cn.sort;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;

/**
 * 数据排序
 * @author root
 *
 */
public class DataSort {

    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
        if (otherArgs.length != 2) {
           System.err.println("Usage: DataSort  ");
           System.exit(2);
        }
        Job job = new Job(conf, "Data Sort");
        job.setJarByClass(DataSort.class);

        //设置输入输出文件目录
        FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
        FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));

        //设置mapper和reduce处理逻辑类
        job.setMapperClass(SortMapper.class);
        job.setReducerClass(SortReduce.class);

        //设置输出key-value类型
        job.setOutputKeyClass(IntWritable.class);
        job.setOutputValueClass(IntWritable.class);

        //提交作业并等待它完成
        System.exit(job.waitForCompletion(true) ? 0 : 1);

    }

}

没事就把自己写过的代码总结哈。