【HBase】自定义 Hbase-MapReduce2

目标 将 fruit 表中的一部分数据（name列），通过 MR 迁入到 fruit2  表中。 分步实现 1．构建 Fruit2Mapper 类，用于读取 fruit 表中的数据

package com.chris.hbase.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 org.apache.hadoop.mapreduce.Mapper;

import java.io.IOException;

public class Fruit2Mapper extends TableMapper {

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

2．构建 Fruit2Reducer 类，用于将读取到的 fruit 表中的数据写入到 fruit2 表中

package com.chris.hbase.mr2;

import org.apache.hadoop.hbase.client.Mutation;
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 org.apache.hadoop.mapreduce.Reducer;

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 put : values) {
            context.write(NullWritable.get(),put);
        }
    }
}

3.  构建Driver类驱动

package com.chris.hbase.mr2;

import com.chris.hbase.mr1.FruitDriver;
import com.chris.hbase.mr1.FruitMapper;
import com.chris.hbase.mr1.FruitReducer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HbaseConfiguration;
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.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

import javax.management.ImmutableDescriptor;

public class Fruit2Driver implements Tool {
    // 定义一个configuration
    private Configuration configuration = null;
    @Override
    public int run(String[] args) throws Exception {
        // 1. 获取job对象
        Job job = Job.getInstance(configuration);
        // 2. 设置驱动类路径
        job.setJarByClass(Fruit2Driver.class);
        // 3.设置Mapper & 输出的KV类型 / 传入mapper的表是fruit
        TableMapReduceUtil.initTableMapperJob("fruit",
                new Scan(),Fruit2Mapper.class,
                ImmutableBytesWritable.class, Put.class,job);
        // 4.设置Reducer类  / reducer传出的表是fruit2
        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 conf) {
        configuration = conf;
    }

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

    public static void main(String[] args) {
        try {
            // 如果要本地运行，换configuration,还要在resource中添加hbase-site.xml
            Configuration configuration = HbaseConfiguration.create();
//            Configuration configuration = new Configuration();
            int run = ToolRunner.run(configuration, new Fruit2Driver(), args);
            System.exit(run);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

4. 在本地运行，往resource文件夹中添加hbase-site.xml的配置信息

5. 在hbase端口创建fruit2表，运行driver中的主程序

6.查询操作结果