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  此篇为大家带来的是官方HBase-MapReduce与自定义。

  通过HBase的相关JavaAPI，我们可以实现伴随HBase操作的MapReduce过程，比如使用MapReduce将数据从本地文件系统导入到HBase的表中，比如我们从HBase中读取一些原始数据后使用MapReduce做数据分析。

标注： 此处为反爬虫标记：读者可自行忽略 

原文地址：https://buwenbuhuo.blog.csdn.net/

1. 官方HBase-MapReduce

1．查看HBase的MapReduce任务的执行

[bigdata@hadoop002 hbase]$ bin/hbase mapredcp 

上图标记处为所需jar包

2. 环境变量的导入

• 1. 执行环境变量的导入（临时生效，在命令行执行下述操作）

$ export HBASE_HOME=/opt/module/hbase $ export HADOOP_HOME=/opt/module/hadoop-2.7.2 $ export HADOOP_CLASSPATH=`${HBASE_HOME}/bin/hbase mapredcp`  // 也可以直接这样 [bigdata@hadoop002 hbase]$ export HADOOP_CLASSPATH=`/opt/module/hbase/bin/hbase mapredcp`  

配置完成后查看是否成功

• 2. 永久生效：在/etc/profile配置

export HBASE_HOME=/opt/module/hbase export HADOOP_HOME=/opt/module/hadoop-2.7.2 

在hadoop-env.sh中配置：（注意：在for循环之后配）

export HADOOP_CLASSPATH=$HADOOP_CLASSPATH:/opt/module/hbase/lib/* 

• 3. 运行官方的MapReduce任务

– 案例一：统计Student表中有多少行数据

[bigdata@hadoop002 hbase]$ /opt/module/hadoop-2.7.2/bin/yarn jar lib/hbase-server-1.3.1.jar rowcounter student 

– 案例二：使用MapReduce将HDFS导入到HBase

• 1.在本地创建一个tsv格式的文件：fruit.tsv

[bigdata@hadoop002 datas]$ vim fruit.tsv  1001 Apple Red 1002 Pear Yellow 1003 Pineapple Yellow 

• 2.创建HBase表

hbase(main):001:0> create 'fruit','info' 

• 3.在HDFS中创建input_fruit文件夹并上传fruit.tsv文件

[bigdata@hadoop002 datas]$ hadoop fs -mkdir /input_fruit/ [bigdata@hadoop002 datas]$ hadoop fs -put fruit.tsv /input_fruit/ 

• 4.执行MapReduce到HBase的fruit表中

[bigdata@hadoop002 hbase]$ /opt/module/hadoop-2.7.2/bin/yarn jar lib/hbase-server-1.3.1.jar importtsv  -Dimporttsv.columns=HBASE_ROW_KEY,info:name,info:color fruit  hdfs://hadoop002:9000/input_fruit  

• 5.使用scan命令查看导入后的结果

hbase(main):001:0> scan ‘fruit’ 

经过测试证明是没问题的

2. 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。

• 1.构建ReadMapper类，用于读取fruit表中的数据

package com.buwenbuhuo.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; /**  * @author 卜温不火  * @create 2020-05-12 19:32  * com.buwenbuhuo.hbase.mr - the name of the target package where the new class or interface will be created.  * hbase0512 - the name of the current project.  */ public class ReadMapper extends TableMapper<ImmutableBytesWritable,Put> { @Override protected void map(ImmutableBytesWritable key, Result value, Context context) throws IOException, InterruptedException {         Put put = new Put(key.copyBytes()); for (Cell cell : value.rawCells()) { if ("name".equals(Bytes.toString(CellUtil.cloneQualifier(cell)))){                  put.add(cell); } }         context.write(key,put); } } 

• 2. 构建WriteReducer类，用于将读取到的fruit表中的数据写入到fruit_mr表中

package com.buwenbuhuo.hbase.mr; 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; /**  * @author 卜温不火  * @create 2020-05-12 19:32  * com.buwenbuhuo.hbase.mr - the name of the target package where the new class or interface will be created.  * hbase0512 - the name of the current project.  */ public class WriteReducer extends TableReducer<ImmutableBytesWritable,Put, NullWritable> { @Override protected void reduce(ImmutableBytesWritable key, Iterable<Put> values, Context context) throws IOException, InterruptedException { for (Put value : values) {             context.write(NullWritable.get(),value); } } } 

• 3. 构建Driver用于组装运行Job任务

package com.buwenbuhuo.hbase.mr; import org.apache.hadoop.conf.Configuration; 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.HRegionPartitioner; import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil; import org.apache.hadoop.mapreduce.Job; import java.io.IOException; /**  * @author 卜温不火  * @create 2020-05-12 19:32  * com.buwenbuhuo.hbase.mr - the name of the target package where the new class or interface will be created.  * hbase0512 - the name of the current project.  */ public class Driver { public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {          Configuration conf = HBaseConfiguration.create();         conf.set("hbase.zookeeper.quorum", "hadoop002,hadoop003,hadoop004");         conf.set("hbase.zookeeper.property.clientPort", "2181");          Job job = Job.getInstance();          job.setJarByClass(Driver.class);          Scan scan = new Scan();          TableMapReduceUtil.initTableMapperJob( "fruit",                 scan,                 ReadMapper.class,                 ImmutableBytesWritable.class,                 Put.class,                 job         );          job.setNumReduceTasks(100);          TableMapReduceUtil.initTableReducerJob("fruit_mr",WriteReducer.class,job,HRegionPartitioner.class);          job.waitForCompletion(true); } } 

• 4. 打包并上传
  
  
• 5. 创建表

hbase(main):003:0> create 'fruit_mr','info' 

• 6. 运行验证

[bigdata@hadoop002 hbase]$ hadoop jar hbase-0512-1.0-SNAPSHOT.jar com.buwenbuhuo.hbase.mr.Driver  

hbase(main):005:0> scan 'fruit_mr' 

3. 自定义HBase-MapReduce2

目标：实现将HDFS中的数据写入到HBase表中。

• 1. 构建ReadFruitFromHDFSMapper于读取HDFS中的文件数据

package com.buwenbuhuo.hbase.mr2; import org.apache.hadoop.hbase.client.Put; import org.apache.hadoop.hbase.io.ImmutableBytesWritable; import org.apache.hadoop.hbase.util.Bytes; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Mapper; import java.io.IOException; /**  * @author 卜温不火  * @create 2020-05-12 22:41  * com.buwenbuhuo.hbase.mr2 - the name of the target package where the new class or interface will be created.  * hbase0512 - the name of the current project.  */ public class ReadMapper extends Mapper<LongWritable, Text, ImmutableBytesWritable, Put> { @Override protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {          String[] split = value.toString().split("t"); if (split.length <= 3){ return; }          Put put = new Put(Bytes.toBytes(split[0]));          put.addColumn(Bytes.toBytes("info"),Bytes.toBytes("name"),Bytes.toBytes(split[1]));         put.addColumn(Bytes.toBytes("info"),Bytes.toBytes("color"),Bytes.toBytes(split[2]));          context.write(new ImmutableBytesWritable(Bytes.toBytes(split[0])),put); } } 

• 2. 构建WriteFruitMRFromTxtReducer类

package com.buwenbuhuo.hbase.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; /**  * @author 卜温不火  * @create 2020-05-12 23:09  * com.buwenbuhuo.hbase.mr2 - the name of the target package where the new class or interface will be created.  * hbase0512 - the name of the current project.  */ public class WriteReducer extends TableReducer<ImmutableBytesWritable, Put, NullWritable> { @Override protected void reduce(ImmutableBytesWritable key, Iterable<Put> values, Context context) throws IOException, InterruptedException { for (Put value : values){             context.write(NullWritable.get(),value); } } } 

• 3.创建Driver

package com.buwenbuhuo.hbase.mr2; import com.buwenbuhuo.hbase.mr.WriteReducer; 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.io.ImmutableBytesWritable; import org.apache.hadoop.hbase.mapreduce.HRegionPartitioner; import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import java.io.IOException; /**  * @author 卜温不火  * @create 2020-05-12 23:09  * com.buwenbuhuo.hbase.mr2 - the name of the target package where the new class or interface will be created.  * hbase0512 - the name of the current project.  */ public class Driver { public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {         Configuration conf = HBaseConfiguration.create();         conf.set("hbase.zookeeper.quorum", "hadoop002,hadoop003,hadoop004");         Job job = Job.getInstance(conf);          job.setJarByClass(Driver.class);          job.setMapperClass(ReadMapper.class);          job.setMapOutputKeyClass(ImmutableBytesWritable.class);         job.setMapOutputValueClass(Put.class);          FileInputFormat.setInputPaths(job,new Path("/input_fruit"));          job.setNumReduceTasks(10);          TableMapReduceUtil.initTableReducerJob("fruit_mr", WriteReducer.class,job, HRegionPartitioner.class);          job.waitForCompletion(true); } } 

• 4. 打包上传
  
  
• 5.测试运行

[bigdata@hadoop002 hbase]$ hadoop jar hbase-0512-1.0-SNAPSHOT.jar com.buwenbuhuo.hbase.mr2.Driver 

  本次的就到这里了,

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