大数据培训之OutputFormat数据输出

1 OutputFormat接口实现类

大数据培训

2 自定义OutputFormat

大数据培训

3 自定义OutputFormat案例实操

1.需求

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

(1)输入数据

(2)期望输出数据

2.需求分析

大数据培训

3.案例实操

(1)编写FilterMapper类

package com.atguigu.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 {

 

      // 写出

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

  }

}

(2)编写FilterReducer类

package com.atguigu.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 获取一行

      String line = key.toString();

 

       // 2 拼接

      line = line + “\r\n”;

 

       // 3 设置key

       k.set(line);

 

       // 4 输出

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

  }

}

(3)自定义一个OutputFormat类

package com.atguigu.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 {

 

      // 创建一个RecordWriter

      return new FilterRecordWriter(job);

  }

}

(4)编写RecordWriter类

package com.atguigu.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 获取文件系统

      FileSystem fs;

 

      try {

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

 

         // 2 创建输出文件路径

         Path atguiguPath = new Path(“e:/atguigu.log”);

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

 

         // 3 创建输出流

         atguiguOut = fs.create(atguiguPath);

         otherOut = fs.create(otherPath);

      } catch (IOException e) {

         e.printStackTrace();

      }

  }

 

  @Override

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

 

      // 判断是否包含“atguigu”输出到不同文件

      if (key.toString().contains(“atguigu”)) {

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

      } else {

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

      }

  }

 

  @Override

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

 

      // 关闭资源

IOUtils.closeStream(atguiguOut);

      IOUtils.closeStream(otherOut);   }

}

(5)编写FilterDriver类

package com.atguigu.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 {

 

// 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:/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);

  }

}

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