如何利用mapreduce批量读写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();
        }  

    }
}

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

//load ntf_data to hbase
package com.ntf.data;  

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.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.client.HBaseAdmin;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
import org.apache.hadoop.hbase.mapreduce.TableReducer;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;
import org.apache.hadoop.util.GenericOptionsParser;  

public class BulkImportData {  

    public static class TokenizerMapper extends
            Mapper<Object, Text, Text, Text> {
        public Text _key = new Text();
        public Text _value = new Text();
        public void map(Object key, Text value, Context context)
                throws IOException, InterruptedException {
            String[] splits = value.toString().split(",");
            if(splits.length==3){
                InputSplit inputSplit=(InputSplit)context.getInputSplit();
                String filename=((FileSplit)inputSplit).getPath().getName();
                filename = filename.replace("mv_", "");
                filename = filename.replace(".txt", "");
                _key.set(splits[0]+"_"+filename);
                context.write(_key, value);
            }
        }
    }  

    public static class IntSumReducer extends
            TableReducer<Text, Text, ImmutableBytesWritable> {
        public void reduce(Text key, Iterable<Text> values,
                Context context) throws IOException, InterruptedException {
            Iterator<Text> itr = values.iterator();
            while(itr.hasNext()){
                Text t = itr.next();
                String[] strs = t.toString().split(",");
                if(strs.length!=3)continue;
                Put put = new Put(key.getBytes());
                put.add(Bytes.toBytes("content"), Bytes.toBytes("score"), Bytes.toBytes(strs[1]));
                put.add(Bytes.toBytes("content"), Bytes.toBytes("date"), Bytes.toBytes(strs[2]));
                context.write(new ImmutableBytesWritable(key.getBytes()), put);
            }
        }
    }  

    public static void main(String[] args) throws Exception {
        String tablename = "ntf_data";
        Configuration conf = HBaseConfiguration.create();
        HBaseAdmin admin = new HBaseAdmin(conf);
        if (admin.tableExists(tablename)) {
            admin.disableTable(tablename);
            admin.deleteTable(tablename);
        }
        HTableDescriptor htd = new HTableDescriptor(tablename);
        HColumnDescriptor hcd = new HColumnDescriptor("content");
        htd.addFamily(hcd);
        admin.createTable(htd);
        String[] otherArgs = new GenericOptionsParser(conf, args)
                .getRemainingArgs();
        if (otherArgs.length != 1) {
            System.err
                    .println("Usage: wordcount <in> <out>" + otherArgs.length);
            System.exit(2);
        }
        Job job = new Job(conf, "word count");
        job.setMapperClass(TokenizerMapper.class);
        job.setJarByClass(BulkImportData.class);
        job.setNumReduceTasks(5);
        FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
        TableMapReduceUtil.initTableReducerJob(tablename, IntSumReducer.class,
                job);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}

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