如何利用mapreduce访问hbase数据

package com.mr.test;  

import java.io.IOException;
import java.util.Iterator;  

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.KeyValue;
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.util.Bytes;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.log4j.Logger;  

public class MRHbase {
    private static Logger log = Logger.getLogger(MRHbase.class);
    public static String family = "charactor";
    public static String col = "hobby";  

    public static class HMap extends TableMapper<Text, Text> {
        @Override
        protected void map(ImmutableBytesWritable key, Result value,
                Context context) throws IOException, InterruptedException {
//          KeyValue kv = value.getColumnLatest(family.getBytes(),
//                  col.getBytes());
//          context.write(new Text(Bytes.toString(kv.getKey())),
//                  new Text(Bytes.toString(kv.getValue())));
            byte[] v = value.getValue(family.getBytes(), col.getBytes());
            byte[] r = value.getRow();
            context.write(new Text(Bytes.toString(v)), new Text(Bytes.toString(r)));
        }
    }  

    public static class Reduce extends MapReduceBase implements
            Reducer<Text, Text, Text, Text> {
        public void reduce(Text key, Iterator<Text> values,
                OutputCollector<Text, Text> output, Reporter reporter)
                throws IOException {
            while (values.hasNext()) {
                output.collect(key, values.next());
            }
        }
    }  

    public static void main(String[] args) {
        Configuration conf = HBaseConfiguration.create();
        try {
            Job job = new Job(conf, "hbase test");
            job.setJarByClass(MRHbase.class);
            Scan scan = new Scan();
            scan.addColumn(family.getBytes(), col.getBytes());
            TableMapReduceUtil.initTableMapperJob("person", scan, HMap.class,
                    Text.class, Text.class, job);
            job.setOutputFormatClass(TextOutputFormat.class);
            FileOutputFormat.setOutputPath(job, new Path(args[0]));
            job.waitForCompletion(true);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }  

    }
}

注：要把zookeeper添加到hadoop/lib目录下，master&slaves

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