import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.client.*;
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
 
 java.io.IOException;
import java.util.ArrayList;
import java.util.List;
/**
 * mapreduce操作hbase
 * @author wilson
 *
 */
public class HBaseMr {
    /**
     * 建立hbase配置
     */
    static Configuration config = null;
    static {
        config = HBaseConfiguration.create();
        config.set("hbase.zookeeper.quorum"
 
, "192.168.10.71,192.168.10.72,192.168.10.73");
        config.set("hbase.zookeeper.property.clientPort", "2181");
    }
    /**
     * 表資訊
     */
    public static final String tableName = "word";//表名1
    public static final String colf = "content";//列族
    public static final String col = "info";//列
    public static final String tableName2 = "stat";//表名2
    /**
     * 初始化表結構，及其資料
     */
    public static void initTB() {
        HTable table=null;
        HBaseAdmin admin=null;
        try {
            admin = new HBaseAdmin(config);//建立表管理
            /*刪除表*/
            if (admin.tableExists(tableName)||admin.tableExists(tableName2)) {
                System.out.println("table is already exists!");
                admin.disableTable(tableName);
                admin.deleteTable(tableName);
                admin.disableTable(tableName2);
                admin.deleteTable(tableName2);
            }
            /*建立表*/
                HTableDescriptor desc = new HTableDescriptor(tableName);
                HColumnDescriptor family = new HColumnDescriptor(colf);
                desc.addFamily(family);
                admin.createTable(desc);
                HTableDescriptor desc2 = new HTableDescriptor(tableName2);
                HColumnDescriptor family2 = new HColumnDescriptor(colf);
                desc2.addFamily(family2);
                admin.createTable(desc2);
            /*插入資料*/
                table = new HTable(config,tableName);
                table.setAutoFlush(false);
                table.setWriteBufferSize(500);
                List<Put> lp = new ArrayList<Put>();
                Put p1 = new Put(Bytes.toBytes("1"));
                p1.add(colf.getBytes(), col.getBytes(), ("The Apache Hadoop software library is a framework").getBytes());
                lp.add(p1);
                Put p2 = new Put(Bytes.toBytes("2"));p2.add(colf.getBytes(),col.getBytes(),("The common utilities that support the other Hadoop modules").getBytes());
                lp.add(p2);
                Put p3 = new Put(Bytes.toBytes("3"));
                p3.add(colf.getBytes(), col.getBytes(),("Hadoop by reading the documentation").getBytes());
                lp.add(p3);
                Put p4 = new Put(Bytes.toBytes("4"));
                p4.add(colf.getBytes(), col.getBytes(),("Hadoop from the release page").getBytes());
                lp.add(p4);
                Put p5 = new Put(Bytes.toBytes("5"));
                p5.add(colf.getBytes(), col.getBytes(),("Hadoop on the mailing list").getBytes());
                lp.add(p5);
                table.put(lp);
                table.flushCommits();
                lp.clear();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if(table!=null){
                    table.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    /**
     * MyMapper 繼承 TableMapper
     * TableMapper<Text,IntWritable> 
     * Text:輸出的key型別，
     * IntWritable：輸出的value型別
     */
    public static class MyMapper extends TableMapper<Text, IntWritable> {
        private static IntWritable one = new IntWritable(1);
        private static Text word = new Text();
        @Override
        //輸入的型別為：key：rowKey； value：一行資料的結果集Result
        protected void map(ImmutableBytesWritable key, Result value,
                Context context) throws IOException, InterruptedException {
            //獲取一行資料中的colf：col
            String words = Bytes.toString(value.getValue(Bytes.toBytes(colf), Bytes.toBytes(col)));// 表裡面只有一個列族，所以我就直接獲取每一行的值
            //按空格分割
            String itr[] = words.toString().split(" ");
            //迴圈輸出word和1
            for (int i = 0; i < itr.length; i++) {
                word.set(itr[i]);
                context.write(word, one);
            }
        }
    }
    /**
     * MyReducer 繼承 TableReducer
     * TableReducer<Text,IntWritable> 
     * Text:輸入的key型別，
     * IntWritable：輸入的value型別，
     * ImmutableBytesWritable：輸出型別，表示rowkey的型別
     */
    public static class MyReducer extends
            TableReducer<Text, IntWritable, ImmutableBytesWritable> {
        @Override
        protected void reduce(Text key, Iterable<IntWritable> values,
                Context context) throws IOException, InterruptedException {
            //對mapper的資料求和
            int sum = 0;
            for (IntWritable val : values) {//疊加
                sum += val.get();
            }
            // 建立put，設定rowkey為單詞
            Put put = new Put(Bytes.toBytes(key.toString()));
            // 封裝資料
            put.add(Bytes.toBytes(colf), Bytes.toBytes(col),Bytes.toBytes(String.valueOf(sum)));
            //寫到hbase,需要指定rowkey、put
            context.write(new ImmutableBytesWritable(Bytes.toBytes(key.toString())),put);
        }
    }

    public static void main(String[] args) throws IOException,
            ClassNotFoundException, InterruptedException {
        config.set("df.default.name", "hdfs://192.168.10.71:9000/");//設定hdfs的預設路徑
        config.set("hadoop.job.ugi", "hadoop,hadoop");//使用者名稱，組
        config.set("mapred.job.tracker", "192.168.10.71:9001");//設定jobtracker在哪
        //初始化表
        initTB();//初始化表
        //建立job
        Job job = new Job(config, "HBaseMr");//job
        job.setJarByClass(HBaseMr.class);//主類
        //建立scan
        Scan scan = new Scan();
        //可以指定查詢某一列
        scan.addColumn(Bytes.toBytes(colf), Bytes.toBytes(col));
        //建立查詢hbase的mapper，設定表名、scan、mapper類、mapper的輸出key、mapper的輸出value
        TableMapReduceUtil.initTableMapperJob(tableName, scan, MyMapper.class,Text.class, IntWritable.class, job);
        //建立寫入hbase的reducer，指定表名、reducer類、job
        TableMapReduceUtil.initTableReducerJob(tableName2, MyReducer.class, job);
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}