package com.demo.mapreduce.outputformat;

import java.io.IOException;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.NullWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Mapper;

public class FilterMapper extends Mapper<LongWritable, Text, Text, NullWritable>{

   @Override

   protected void map(LongWritable key, Text value, Context context)  throws IOException, InterruptedException {

      // 寫出

      context.write(value, NullWritable.get());

   }

}

package com.demo.mapreduce.outputformat;

import java.io.IOException;

import org.apache.hadoop.io.NullWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Reducer;

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 獲取一行

      String line = key.toString();

       // 2 拼接

      line = line + "\r\n";

       // 3 設定key

       k.set(line);

       // 4 輸出

      context.write(k, NullWritable.get());

   }

}

package com.demo.mapreduce.outputformat;

import java.io.IOException;

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;

public class FilterOutputFormat extends FileOutputFormat<Text, NullWritable>{

   @Override

   public RecordWriter<Text, NullWritable> getRecordWriter(TaskAttemptContext job)         throws IOException, InterruptedException {

      // 建立一個RecordWriter

      return new FilterRecordWriter(job);

   }

}

package com.demo.mapreduce.outputformat;

import java.io.IOException;

import org.apache.hadoop.fs.FSDataOutputStream;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.io.NullWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.RecordWriter;

import org.apache.hadoop.mapreduce.TaskAttemptContext;

public class FilterRecordWriter extends RecordWriter<Text, NullWritable> {

   FSDataOutputStream atguiguOut = null;

   FSDataOutputStream otherOut = null;

   public FilterRecordWriter(TaskAttemptContext job) {

      // 1 獲取檔案系統

      FileSystem fs;

      try {

          fs = FileSystem.get(job.getConfiguration());

          // 2 建立輸出檔案路徑

          Path atguiguPath = new Path("e:/baidu.log");

          Path otherPath = new Path("e:/other.log");

          // 3 建立輸出流

          atguiguOut = fs.create(atguiguPath);

          otherOut = fs.create(otherPath);

      } catch (IOException e) {

          e.printStackTrace();

      }

   }

   @Override

   public void write(Text key, NullWritable value) throws IOException, InterruptedException {

      // 判斷是否包含“baidu”輸出到不同檔案

      if (key.toString().contains("baidu")) {

          atguiguOut.write(key.toString().getBytes());

      } else {

          otherOut.write(key.toString().getBytes());

      }

   }

   @Override

   public void close(TaskAttemptContext context) throws IOException, InterruptedException {

      // 關閉資源

IOUtils.closeStream(atguiguOut);

      IOUtils.closeStream(otherOut);  }

}

package com.demo.mapreduce.outputformat;

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;

public class FilterDriver {

   public static void main(String[] args) throws Exception {

// 輸入輸出路徑需要根據自己電腦上實際的輸入輸出路徑設定

args = new String[] { "e:/input/inputoutputformat", "e:/output2" };

      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);

      // 要將自定義的輸出格式元件設定到job中

      job.setOutputFormatClass(FilterOutputFormat.class);

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

      // 雖然我們自定義了outputformat，但是因為我們的outputformat繼承自fileoutputformat

      // 而fileoutputformat要輸出一個_SUCCESS檔案，所以，在這還得指定一個輸出目錄

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

      boolean result = job.waitForCompletion(true);

      System.exit(result ? 0 : 1);

   }

}