source: sample/hadoop-0.16/tw/org/nchc/code/HBaseRecord2.java @ 27

/**
 * Program: HBaseRecord.java
 * Editor: Waue Chen 
 * From :  NCHC. Taiwn
 * Last Update Date: 07/01/2008
 */

/**
 * Purpose : 
 *  Parse your record and then store in HBase.
 * 
 * HowToUse : 
 *  Make sure Hadoop file system and Hbase are running correctly.
 *  1. put test.txt in t1 directory which content is 
  ---------------
  name:locate:years 
  waue:taiwan:1981
  shellon:taiwan:1981
  ---------------
 *  2. hadoop_root/$ bin/hadoop dfs -put t1 t1
    ----------------
 * Check Result:
 *  Go to hbase console, type : 
 *    hql > select * from t1_table; 
08/06/06 12:20:48 INFO hbase.HTable: Creating scanner over t1_table starting at key 
+-------------------------+-------------------------+-------------------------+
| Row                     | Column                  | Cell                    |
+-------------------------+-------------------------+-------------------------+
| 0                       | person:locate           | locate                  |
+-------------------------+-------------------------+-------------------------+
| 0                       | person:name             | name                    |
+-------------------------+-------------------------+-------------------------+
| 0                       | person:years            | years                   |
+-------------------------+-------------------------+-------------------------+
| 19                      | person:locate           | taiwan                  |
+-------------------------+-------------------------+-------------------------+
| 19                      | person:name             | waue                    |
+-------------------------+-------------------------+-------------------------+
| 19                      | person:years            | 1981                    |
+-------------------------+-------------------------+-------------------------+
| 36                      | person:locate           | taiwan                  |
+-------------------------+-------------------------+-------------------------+
| 36                      | person:name             | shellon                 |
+-------------------------+-------------------------+-------------------------+
| 36                      | person:years            | 1981                    |
+-------------------------+-------------------------+-------------------------+
3 row(s) in set. (0.04 sec)
 */




package tw.org.nchc.code;

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

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapred.TableReduce;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.MapWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.lib.IdentityMapper;
import org.apache.hadoop.mapred.lib.IdentityReducer;


public class HBaseRecord2 {

  /* Denify parameter */
  static String[] bf = {"person:name","person:local","person:birthyear"};
  // file path in hadoop file system (not phisical file system)
  String file_path = "/user/waue/t1/test.txt";
  // Hbase table name
  String table_name = "testtable";
  
  
  // setup MapTask and Reduce Task
  int mapTasks = 1;
  int reduceTasks = 1;
  
  private static class ReduceClass extends TableReduce<LongWritable, Text> {


    
    // on this sample, map is nonuse, we use reduce to handle
    public void reduce(LongWritable key, Iterator<Text> values,
        OutputCollector<Text, MapWritable> output, Reporter reporter)
        throws IOException {
      // this map holds the columns per row
      MapWritable map = new MapWritable();  
      // values.next().getByte() can get value and transfer to byte form, 
      String stro = new String(values.next().getBytes());
      String str[] = stro.split(":");
      
      int length = bf.length;
      
      // Column id is created dymanically, 
      Text[] col_n = new Text[length];
      byte[][] b_l = new byte[length][];
      // contents must be ImmutableBytesWritable
      ImmutableBytesWritable[] w_l = new ImmutableBytesWritable[length];
      map.clear();
      for(int i = 0; i < length; i++){
        col_n[i] = new Text(bf[i]);
        b_l[i] = str[i].getBytes();
        w_l[i] = new ImmutableBytesWritable(b_l[i]);
        // populate the current row
        map.put(col_n[i], w_l[i]);
      }
      // add the row with the key as the row id
      output.collect(new Text(key.toString()), map);
    }
  }

  private HBaseRecord2() {
  }

  /**
   * Runs the demo.
   */
  public static void main(String[] args) throws IOException {

    
    HBaseRecord2 setup = new HBaseRecord2();
    String[] tmp = bf[0].split(":");
    String[] CF = {tmp[0]};
    BuildHTable build_table = new BuildHTable(setup.table_name, CF);
    if (!build_table.checkTableExist(setup.table_name)) {
      if (!build_table.createTable()) {
        System.out.println("create table error !");
      }
    } else {
      System.out.println("Table \"" + setup.table_name
          + "\" has already existed !");
    }
    
    JobConf conf = new JobConf(HBaseRecord2.class);

    //Job name; you can modify to any you like  
    conf.setJobName("PersonDataBase");

    // Hbase table name must be correct , in our profile is t1_table
    TableReduce.initJob(setup.table_name, ReduceClass.class, conf);
    
    // below are map-reduce profile
    conf.setNumMapTasks(setup.mapTasks);
    conf.setNumReduceTasks(setup.reduceTasks);
    conf.setInputPath(new Path(setup.file_path));
    conf.setMapperClass(IdentityMapper.class);
    conf.setCombinerClass(IdentityReducer.class);
    conf.setReducerClass(ReduceClass.class);
    JobClient.runJob(conf);
  }
}