hadoop案例：自定义outputformat

需求

过滤输入的log日志，包含hadoop的网站输出到e:/hadoop.log，不包含hadoop的网站输出到e:/other.log

输入数据

log.txt

http://www.baidu.com
http://www.google.com
http://cn.bing.com
http://www.hadoop.com
http://www.sohu.com
http://www.sina.com
http://www.sin2a.com
http://www.sin2desa.com
http://www.sindsafa.com

期望输出数据

需求分析

编写代码

自定义FilterOutputFormat

package com.mr.filteroutformat;

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 org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;


import java.io.IOException;

public class FilterOutputFormat extends FileOutputFormat<Text, NullWritable> {
    @Override
    public RecordWriter<Text, NullWritable> getRecordWriter(TaskAttemptContext job) throws IOException, InterruptedException {



        return new FilterRecordWriter(job);
    }
}

自定义FilterRecordWriter

package com.mr.filteroutformat;

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 FilterRecordWriter extends RecordWriter<Text, NullWritable> {


    //构造器方法
    FSDataOutputStream hadoopOut = null;
    FSDataOutputStream otherOut = null;


    public FilterRecordWriter(TaskAttemptContext job) {
        FileSystem fs;
        try {
            fs = FileSystem.get(job.getConfiguration());

            // 2 创建输出文件路径
            Path hadoopPath = new Path("E:\Hadoop\src\main\resources\ouput\filterlog\hadoop.log");
            Path otherPath = new Path("E:\Hadoop\src\main\resources\ouput\filterlog\.other.log");

            // 3 创建输出流
            hadoopOut = fs.create(hadoopPath);
            otherOut = fs.create(otherPath);
        } catch (IOException e) {
            e.printStackTrace();
        }


    }

    @Override
    public void write(Text key, NullWritable value) throws IOException, InterruptedException {
// 判断是否包含“hadoop”输出到不同文件
        if (key.toString().contains("hadoop")) {
            hadoopOut.write(key.toString().getBytes());
        } else {
            otherOut.write(key.toString().getBytes());
        }

    }

    @Override
    public void close(TaskAttemptContext taskAttemptContext) throws IOException, InterruptedException {
// 关闭资源
        IOUtils.closeStream(hadoopOut);
        IOUtils.closeStream(otherOut);

    }
}

Mapper类

package com.mr.filteroutformat;

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 FilterMapper extends Mapper<LongWritable, Text,Text, NullWritable> {
    @Override
    protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
        context.write(value,NullWritable.get());
    }
}

Reducer类

package com.mr.filteroutformat;

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

import java.io.IOException;

public class FilterReducer extends Reducer<Text, NullWritable,Text,NullWritable> {
    Text k = new Text();
    @Override
    protected void reduce(Text key, Iterable<NullWritable> values, Context context) throws IOException, InterruptedException {
        // 1 获取一行
        String line = key.toString();

        // 2 拼接
        line = line + "rn";

        // 3 设置key
        k.set(line);

        // 4 输出
        context.write(k, NullWritable.get());


    }
}

Driver类

package com.mr.filteroutformat;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
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 FilterDriver  {
    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {

        // 输入输出路径需要根据自己电脑上实际的输入输出路径设置
        args = new String[] { "E:\Hadoop\src\main\resources\input\filterlog", "E:\Hadoop\src\main\resources\ouput\filterlog" };

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

        job.setJarByClass(FilterDriver.class);
        job.setMapperClass(FilterMapper.class);
        job.setReducerClass(FilterReducer.class);

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

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

        // 要将自定义的输出格式组件设置到job中
        job.setOutputFormatClass(FilterOutputFormat.class);

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

        // 虽然我们自定义了outputformat，但是因为我们的outputformat继承自fileoutputformat
        // 而fileoutputformat要输出一个_SUCCESS文件，所以，在这还得指定一个输出目录
        FileOutputFormat.setOutputPath(job, new Path(args[1]));

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

}

执行结果

最后

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