大数据培训之数据清洗（ETL）

package com.atguigu.mapreduce.weblog;

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 LogMapper extends Mapper<LongWritable, Text, Text, NullWritable>{

  Text k = new Text();

  @Override

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

      // 1 获取1行数据

      String line = value.toString();

      // 2 解析日志

      boolean result = parseLog(line,context);

      // 3 日志不合法退出

      if (!result) {

         return;

      }

      // 4 设置key

      k.set(line);

      // 5 写出数据

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

  }

  // 2 解析日志

  private boolean parseLog(String line, Context context) {

      // 1 截取

      String[] fields = line.split(” “);

      // 2 日志长度大于11的为合法

      if (fields.length > 11) {

         // 系统计数器

         context.getCounter(“map”, “true”).increment(1);

         return true;

      }else {

         context.getCounter(“map”, “false”).increment(1);

         return false;

      }

  }

}

package com.atguigu.mapreduce.weblog;

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 LogDriver {

  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/inputlog”, “e:/output1” };

      // 1 获取job信息

      Configuration conf = new Configuration();

      Job job = Job.getInstance(conf);

      // 2 加载jar包

      job.setJarByClass(LogDriver.class);

      // 3 关联map

      job.setMapperClass(LogMapper.class);

      // 4 设置最终输出类型

      job.setOutputKeyClass(Text.class);

      job.setOutputValueClass(NullWritable.class);

      // 设置reducetask个数为0

      job.setNumReduceTasks(0);

      // 5 设置输入和输出路径

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

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

      // 6 提交

      job.waitForCompletion(true);

  }

}