HBase到MR再到HBase

HBase到MR再到HBase

自定义Hbase-MapReDuce2——从Hbase表中读取数据，经过MR，再返回到一个新的Hbase表中

文章目录

1）需求分析2）编写Mapper3）编写Reducer4）编写Driver5）本地连接Hbase6）检验

1）需求分析

从fruit表中抽出info:name信息，放入fruit2表中

2）编写Mapper

package com.yingzi.mr2;

import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableMapper;
import org.apache.hadoop.hbase.util.Bytes;

import java.io.IOException;


public class Fruit2Mapper extends TableMapper {

    @Override
    protected void map(ImmutableBytesWritable key, Result value, Context context) throws IOException, InterruptedException {

        //构建Put对象
        Put put = new Put(key.get());

        //1.获取数据
        for (Cell cell : value.rawCells()) {

            //2.判断当前的cell是否为“name”列
            if ("name".equals(Bytes.toString(CellUtil.cloneQualifier(cell)))){
                //3.给Put对象赋值
                put.add(cell);
            }
        }

        //4.写出
        context.write(key,put);
    }
}

3）编写Reducer

package com.yingzi.mr2;

import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableReducer;
import org.apache.hadoop.io.NullWritable;

import java.io.IOException;


public class Fruit2Reducer extends TableReducer {

    @Override
    protected void reduce(ImmutableBytesWritable key, Iterable values, Context context) throws IOException, InterruptedException {

        //遍历写出
        for (Put value : values) {
            context.write(NullWritable.get(),value);
        }

    }
}

4）编写Driver

package com.yingzi.mr2;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;


public class Fruit2Driver implements Tool {

    //定义配置信息
    Configuration configuration = null;

    @Override
    public int run(String[] strings) throws Exception {
        //1.获取Job对象
        Job job = Job.getInstance(configuration);

        //2.设置主类路径
        job.setJarByClass(Fruit2Driver.class);

        //3.设置Mapper&输出KV类型
        TableMapReduceUtil.initTableMapperJob("fruit",
                new Scan(),
                Fruit2Mapper.class,
                ImmutableBytesWritable.class,
                Put.class,
                job);

        //4.设置Reducer&输出的表
        TableMapReduceUtil.initTableReducerJob("fruit2",
                Fruit2Reducer.class,
                job);

        //5.提交任务
        boolean result = job.waitForCompletion(true);

        return result?0:1;
    }

    @Override
    public void setConf(Configuration configuration) {
        this.configuration = configuration;
    }

    @Override
    public Configuration getConf() {
        return configuration;
    }

    public static void main(String[] args) {

        try {
            Configuration configuration = new Configuration();
            ToolRunner.run(configuration,new Fruit2Driver(),args);
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

5）本地连接Hbase

在resources目录下配置hbase-site.xml文件

内容为虚拟机上的/opt/module/hbase-1.3.1/conf/hbase-site.xml

6）检验

运行Driver程序，查看“fruit2”表信息如下：