mapreduce-自定义outputformat

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常见的outputformat实现类

使用场景：

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实例操作：

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Mapper：

package com.out.io;

import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;

import java.io.IOException;

public class outMapper extends Mapper<LongWritable, Text,Text, NullWritable> {
    @Override
    protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
        String k = value.toString() + "\n";
        Text kk  = new Text();
        kk.set(k);
        context.write(kk,NullWritable.get());
    }
}

Reducer：

package com.out.io;

import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;

import java.io.IOException;

public class outReducer extends Reducer<Text, NullWritable,Text,NullWritable> {
    @Override
    protected void reduce(Text key, Iterable<NullWritable> values, Context context) throws IOException, InterruptedException {
        for (NullWritable i:values) {
            context.write(key,NullWritable.get());
        }
    }
}

outformat：

package com.out.io;

import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.lib.FilterOutputFormat;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import java.io.IOException;

//import javax.xml.soap.Text;

public class outformat extends FileOutputFormat<Text, NullWritable> {

    @Override
    public RecordWriter<Text, NullWritable> getRecordWriter(TaskAttemptContext taskAttemptContext) throws IOException, InterruptedException {
        return new FilterRecord(taskAttemptContext);
    }
}

文件读写类，实现主要逻辑：RecordWriter

package com.out.io;

//import org.apache.commons.lang.ObjectUtils;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;

import java.io.IOException;

public class FilterRecord extends RecordWriter<Text, NullWritable> {

    FSDataOutputStream fosatguigu = null;
    FSDataOutputStream fosother = null;

    public FilterRecord(TaskAttemptContext job) {
        FileSystem fs;
        try{
            fs = FileSystem.get(job.getConfiguration());
            fosatguigu = fs.create(new Path("d:/mapreduceoutput/out5/atguidu.log"));
            fosother = fs.create(new Path("d:/mapreduceoutput/out5/other.log"));

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void write(Text text, NullWritable nullWritable) throws IOException, InterruptedException {

        if (text.toString().contains("atguigu")){
            fosatguigu.write(text.toString().getBytes());
        } else {
            fosother.write(text.toString().getBytes());
        }
    }

    @Override
    public void close(TaskAttemptContext taskAttemptContext) throws IOException, InterruptedException {

        //fosatguigu.close();
        //fosother.close();
        IOUtils.closeStream(fosatguigu);
        IOUtils.closeStream(fosother);
    }
}

Driver：

package com.out.io;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
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 java.io.IOException;

public class outDriver {
    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {

        args = new String[]{"d:/mapreduceinput/input5","d:/mapreduceoutput/out5"};

        Job job = Job.getInstance(new Configuration());

        job.setJarByClass(outDriver.class);
        job.setMapperClass(outMapper.class);
        job.setReducerClass(outReducer.class);

        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(NullWritable.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(NullWritable.class);

        job.setOutputFormatClass(outformat.class);

        FileInputFormat.setInputPaths(job,new Path(args[0]));
        FileOutputFormat.setOutputPath(job,new Path(args[1]));

        boolean res = job.waitForCompletion(true);
        System.exit(res?0:1);
    }
}