MapReduce修改輸出的檔案名

MapReduce預設輸出的檔案名稱格式如下：part-r-00000

自定義名稱，比如editName，則輸出的檔案名稱為：editName-r-0000，此方法沒有徹底修改整個檔案名，隻修改了一部分

方法如下

重寫TextOutPutFormat的setOutPutName方法，因為setOutPutName是protected方法，是以隻能通過重寫的方式來修改

/**
 * 
 */
package com.zhen.outPutName;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;

/**
 * @author FengZhen
 * setOutputName是protected方法，是以無法直接調用，隻能自定義TextOutPutFormat重寫該方法
 */
public class MyOutPutFormat extends TextOutputFormat<Text, IntWritable>{

    protected static void setOutputName(JobContext job, String name) {  
        job.getConfiguration().set(BASE_OUTPUT_NAME, name);  
      }  
}      

/**
 * 
 */
package com.zhen.outPutName;

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.NullWritable;
import org.apache.hadoop.io.Text;
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.mapreduce.lib.output.TextOutputFormat;

/**
 * @author FengZhen
 * hadoop jar /Users/FengZhen/Desktop/Hadoop/other/mapreduce_jar/OutPutNameTest.jar com.zhen.outPutName.OutPutNameTest /user/hadoop/mapreduce/combinerTest/input /user/hadoop/mapreduce/OutPutNameTest/output/ 
 */
public class OutPutNameTest {

    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
        Configuration configuration = new Configuration();
        Job job = new Job(configuration, OutPutNameTest.class.getSimpleName());
        job.setJarByClass(OutPutNameTest.class);
        job.setMapperClass(MapTest.class);
        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(IntWritable.class);
        
        job.setReducerClass(ReduceTest.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);
        //設定job的輸出類型
        job.setOutputFormatClass(MyOutPutFormat.class);
        
        job.setCombinerClass(ReduceTest.class);
        job.setPartitionerClass(PartitionTest.class);
        job.setNumReduceTasks(2);
        
        //結果名稱如下：editName-r-00000，此方法隻能修改part這一段
        MyOutPutFormat.setOutputName(job, "editName");
        
        FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));
        
        System.exit(job.waitForCompletion(true)?0:1);
    }
    
}