mapreduce读取hbase内容，结果放到hbase中

最新推荐文章于 2025-06-10 00:07:45 发布

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最新推荐文章于 2025-06-10 00:07:45 发布

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分类专栏： hadoop

本文链接：https://blog.youkuaiyun.com/u014034934/article/details/74000426

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本文介绍了一个使用Hadoop MapReduce实现从一个HBase表到另一个HBase表的数据迁移示例。通过自定义Mapper和Reducer，实现了数据的读取、转换及写入过程。

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package hadoop;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
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.hbase.mapreduce.TableMapper;
import org.apache.hadoop.hbase.mapreduce.TableReducer;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper.Context;

import com.sun.jersey.core.util.StringIgnoreCaseKeyComparator;

import hadoop.HbaseMapreduce.HbaseMapper;

public class HbaseToHbase {

	static class HbaseMap extends TableMapper<Text, Text>{
		@Override
		protected void map(ImmutableBytesWritable key, Result value,Context context)
				throws IOException, InterruptedException {
			for(Cell cell :value.rawCells()){
				context.write(new Text(Bytes.toString(CellUtil.cloneRow(cell))),new Text(Bytes.toString(CellUtil.cloneQualifier(cell))+","+Bytes.toString(CellUtil.cloneValue(cell))));
			}
		}
		
	}
	
	static class HbaseRed extends TableReducer<Text, Text, ImmutableBytesWritable>{
		
		@Override
		protected void reduce(Text key, Iterable<Text> values,Context context)
				throws IOException, InterruptedException {
			
			for(Text text :values){
				String line = text.toString();
				String[] lines = line.split(",");
				Put put = new Put(key.toString().getBytes());
				put.add("f".getBytes(), lines[0].getBytes(), lines[1].getBytes());
				context.write(new ImmutableBytesWritable("result".getBytes()), put);
			}
		}
	}
	
	public static void main(String[] args) throws Exception {
		Configuration conf = HBaseConfiguration.create();
		conf.set("hbase.zookeeper.quorum", "192.168.10.250");
		conf.set("hbase.zookeeper.property.clientPort", "2181");
		Job job = Job.getInstance(conf,"hbasedemo");
		job.setJarByClass(HbaseToHbase.class);
		
		List<Scan> list = new ArrayList<Scan>();
		Scan scan = new Scan();
		scan.setCaching(200);
		scan.setCacheBlocks(false);
		scan.setStartRow("row1".getBytes());
		scan.setStopRow("row9".getBytes());
		scan.setAttribute(Scan.SCAN_ATTRIBUTES_TABLE_NAME, "mapreduce".getBytes());
		list.add(scan);
		
		TableMapReduceUtil.initTableMapperJob(list, HbaseMap.class, Text.class,Text.class, job);
		
		TableMapReduceUtil.initTableReducerJob("result", HbaseRed.class, job);
	
		job.waitForCompletion(true);
		return;
	}
}