开发者学堂课程【分布式数据库 HBase 快速入门：自定义 MR1 之 Mapper 】学习笔记，与课程紧密联系，让用户快速学习知识。
课程地址：https://developer.aliyun.com/learning/course/101/detail/1755
自定义 MR1 之 Mapper
内容介绍
一、自定义 MR1 之 Mapper
一、自定义 MR1 之 Mapper
自定义 HBase-MapReduce1
目标：将 fruit 表中的一部分数据，通过 MR 迁入到 fruit_mr 表中。
分步实现:
1．构建 ReadFruitMapper 类，用于读取 fruit 表中的数据
package com.atguigu . hbase_mr;
import java.io.IOException;
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;
Public class ReadFruitMapper extends
TableMapper {
@override
protected void map(ImmutableByteswritable key,Result value,Context context)
throws IOException,InterruptedException {
Tota1 time spent by a17 maps in occupied slots (ms)=5222Tota1 time spent by a17 reduces in occupied slots (ms)=0Total time spent by al7 map tasks (ms)=5222
Tota1 vcore-mi11iseconds taken by a17 map tasks=5222
Total megabyte-mil7iseconds taken by a17 map tasks=5347328
Map-Reduce Framework
Map input records=3Map output records=3Input split bytes=96spi77ed Records=oFailed shuffles=oMerged Map outputs=o
Gc time elapsed (ms)=272CPu time spent (ms)=2510
Physical memory (bytes) snapshot=222109696virtua7 memory (bytes) snapshot=3001012224Tota1 committed heap usage' (bytes)=152043520
ImportTsv
Bad Lines=o
File Input Format counters
Bytes Read=54
File output Format counters
Bytes written=o
[atguigu@hadoop102 hbase]$
/**
*Extends the base Mapper class to add the required input Key
*and value classes.
*
*@param The type of the key.
*@param The type of the value.
*@see org.apache. hadoop. mapreduce.Mapper
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class TableMapper
extends Mapper{
}
import org.apache.hadoop. hbase. mapreduce.TableMapper;
import org.apache. hadoop.hbase.uti1.Bytes;
import java.io.IOException;
public class FruitMapper 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()) ;
//遍历数据
Cell[] cells = value.rawCells();
cell[] cells = value.rawCells();
for (Cell cell : cells){
if ("name".equals(Bytes.toString(CellUtil.cloneQualifier(cell)))){
Putadd(cell);
}
}
