筛选日志并生成序列化文件

news2025/11/8 17:20:37

1.在idea中创建项目 selectData.

2.添加依赖，插件包，指定打包方式，日志文件

大家可以直接从前面项目复制。

3.本次只需要进行序列化操作，所以不需要Reducer模块，编写Mapper模块

package com.maidu.selectdata;

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

import java.io.IOException;

/**
 * @author:yt
 * @since:2024-04-25
 */
public class MyMapper extends Mapper<Object, Text,Text,Text> {
    @Override
    protected void map(Object key, Text value,  Context context) throws IOException, InterruptedException {
         String line =value.toString();
         String []arr=line.split(",");
         if(arr[4].contains("2021/1") ||arr[4].contains("2021/2")){
             context.write(new Text(arr[2]),new Text(arr[4].substring(0,arr[4].indexOf(" "))   ));
         }
    }
}

4、编写Driver模块

package com.maidu.selectdata;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
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.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;

/**
 * @author:yt
 * @since:2024-04-25
 */
public class SelectData {
    public static void main(String[] args) throws Exception {

        Configuration conf =new Configuration();
        String []otherArgs = new GenericOptionsParser(conf,args).getRemainingArgs();
        if(otherArgs.length<2){
            System.out.println("必须输入文件输入路径和输出路径");
            System.exit(2);
        }

        Job job = Job.getInstance(conf,"visit count");
        job.setJarByClass(SelectData.class);
        job.setMapperClass(MyMapper.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);
        //设置输入格式
        job.setInputFormatClass(TextInputFormat.class);
        //设置输出格式
        job.setOutputFormatClass(SequenceFileOutputFormat.class);
        //设置reduce任务为0
        job.setNumReduceTasks(0);
        for(int i=0;i<otherArgs.length-1;i++){
            FileInputFormat.addInputPath(job,new Path(otherArgs[i]));
        }
        FileOutputFormat.setOutputPath(job,new Path(otherArgs[ otherArgs.length-1  ]));
        System.exit( job.waitForCompletion(true)?0:1 );


    }
}