需要一：
將hbase中‘student’表中的info：name和info：age兩列資料取出並寫入到hbase中‘user’表中的basic：XM和basic：NL

class ReadStudentMapper extends TableMapper

package hbaseapi.hbase;


import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
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.NullWritable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop
 
.mapreduce.Mapper.Context;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

public class Student2UserMapReduce extends Configured implements Tool {

    // Step 1 : Mapper
    public static class ReadStudentMapper extends
            TableMapper<ImmutableBytesWritable, Put> {

        @Override
        protected void map(ImmutableBytesWritable key, Result value,
                Context context) throws IOException, InterruptedException {
            // create put ,
            Put put = new Put(key.get());
            // add cell/data to put
            for (Cell cell : value.rawCells()) {
                // get info family
                if ("info".equals(Bytes.toString(CellUtil.cloneFamily(cell)))) {
                    // add name to put
                    if ("name".equals(Bytes.toString(CellUtil
                            .cloneQualifier(cell)))) {
                        put.add(Bytes.toBytes("info"), Bytes.toBytes("XM"),
                                CellUtil.cloneValue(cell));
                    } else if ("age".equals(Bytes.toString(CellUtil
                            .cloneQualifier(cell)))) {
                        put.add(Bytes.toBytes("info"), Bytes.toBytes("NL"),
                                CellUtil.cloneValue(cell));

                    }

                }

            }

            // context output
            context.write(key, put);

        }
    }

    // Step 2 : Reducer

    public static class WriteUserReducer extends
            TableReducer<ImmutableBytesWritable, Put, NullWritable> {

        @Override
        protected void reduce(ImmutableBytesWritable key, Iterable<Put> values,
                Context context) throws IOException, InterruptedException {

            for (Put put : values) {
                context.write(NullWritable.get(), put);
            }

        }

    }

    // Step 3 : Driver
    public int run(String[] args) throws Exception {
        // 1) Configuration
        Configuration conf = this.getConf();
        // 2) create job
        Job job = Job.getInstance(conf, this.getClass().getSimpleName());
        job.setJarByClass(Student2UserMapReduce.class);

        // 3) set job
        // set scan 設定一個查詢範圍或條件
        Scan scan = new Scan();
        // 設定只掃描某些列或列簇
        scan.addFamily(Bytes.toBytes("info"));
        // set Mapper
        TableMapReduceUtil.initTableMapperJob("student", 
                scan, 
                ReadStudentMapper.class,
                ImmutableBytesWritable.class, 
                Put.class, 
                job);
        // set Reducer 
        TableMapReduceUtil.initTableReducerJob(
                "user",
                WriteUserReducer.class, 
                job);

        //set reduce nums 
        job.setNumReduceTasks(1); //at least one ,adjust as required!!

        boolean isSuccess = job.waitForCompletion(true);
        if (!isSuccess) {
            throw new IOException("error with job!");
        }
        return isSuccess ? 0 : 1;

    }

    public static void main(String[] args) throws Exception {
        Configuration conf = HBaseConfiguration.create();
        int status = ToolRunner.run(//
                conf, //
                new Student2UserMapReduce(), //
                args //
                );
        System.exit(status);

    }

}