Apache HBase Client Java API Examples

HBase Client java API
This post describes the java client API for HBase that is used to perform CRUD operations on HBase tables (See, how to create tables.). HBase is written in Java and has a Java Native API. Therefore it provides programmatic access to Data Manipulation Language (DML).
Step 1 - Edit $HOME/.bashrc file by adding the java and hadoop path.

$ sudo gedit $HOME/.bashrc

$HOME/.bashrc file. Add the following line

export CLASSPATH=$CLASSPATH:/usr/local/hbase/lib/*

Step 2 Reload your changed $HOME/.bashrc settings

$ source $HOME/.bashrc

Step 3 - Change the directory to /usr/local/hbase

$ cd /usr/local/hbase

Step 4 - To start up the initial HBase cluster.

$ ./start-hbase.sh

Add all HBase libraries to your java project's class path.

/usrlocal/hbase/lib/*

Inserting Data into Table Using java API (See, how to create tables.).
InsertData.java

import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.util.Bytes;

public class InsertData {
 @SuppressWarnings("deprecation")
 public static void main(String[] args) throws IOException {
  // Instantiating Configuration class
  Configuration config = HBaseConfiguration.create();
  // Instantiating HTable class
  HTable hTable = new HTable(config, "emp");
  // Instantiating Put class
  // accepts a row name.
  Put p = new Put(Bytes.toBytes("2"));
  // adding values using add() method
  // accepts column family name, qualifier/row name ,value
  p.add(Bytes.toBytes("personal data"), Bytes.toBytes("name"),
    Bytes.toBytes("praveen"));
  p.add(Bytes.toBytes("personal data"), Bytes.toBytes("city"),
    Bytes.toBytes("bangalore"));
  p.add(Bytes.toBytes("professional data"), Bytes.toBytes("designation"),
    Bytes.toBytes("software developer"));
  p.add(Bytes.toBytes("professional data"), Bytes.toBytes("salary"),
    Bytes.toBytes("50000"));
  // Saving the put Instance to the HTable.
  hTable.put(p);
  System.out.println("data inserted");
  // closing HTable
  hTable.close();
 }
}

Updating Data into Table Using java API
UpdateData.java

import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.util.Bytes;

public class UpdateData {
 @SuppressWarnings("deprecation")
 public static void main(String[] args) throws IOException {
  // Instantiating Configuration class
  Configuration config = HBaseConfiguration.create();
  // Instantiating HTable class
  HTable hTable = new HTable(config, "emp");
  // Instantiating Put class
  // accepts a row name
  Put p = new Put(Bytes.toBytes("1"));
  // Updating a cell value
  p.add(Bytes.toBytes("personal data"), Bytes.toBytes("city"),
    Bytes.toBytes("hyderabad"));
  // Saving the put Instance to the HTable.
  hTable.put(p);
  System.out.println("data Updated");
  // closing HTable
  hTable.close();
 }
}

Retrieving Data from Table Using java API
RetriveData.java

import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.util.Bytes;

public class RetriveData {
 @SuppressWarnings("deprecation")
 public static void main(String[] args) throws IOException, Exception {
  // Instantiating Configuration class
  Configuration config = HBaseConfiguration.create();
  // Instantiating HTable class
  HTable table = new HTable(config, "emp");
  // Instantiating Get class
  Get g = new Get(Bytes.toBytes("2"));
  // Reading the data
  Result result = table.get(g);
  // Reading values from Result class object
  byte[] value = result.getValue(Bytes.toBytes("personal data"),
    Bytes.toBytes("name"));
  byte[] value1 = result.getValue(Bytes.toBytes("personal data"),
    Bytes.toBytes("city"));
  // Printing the values
  String name = Bytes.toString(value);
  String city = Bytes.toString(value1);
  System.out.println("name: " + name +"  "+ "city: " + city);
  table.close();
 }
}

Deleting Data from Table Using java API
DeleteData.java

import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Delete;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.util.Bytes;

public class DeleteData {
 @SuppressWarnings("deprecation")
 public static void main(String[] args) throws IOException {
  // Instantiating Configuration class
  Configuration conf = HBaseConfiguration.create();
  // Instantiating HTable class
  HTable table = new HTable(conf, "emp");
  // Instantiating Delete class
  Delete delete = new Delete(Bytes.toBytes("2"));
  delete.deleteColumn(Bytes.toBytes("personal data"), Bytes.toBytes("name"));
  delete.deleteFamily(Bytes.toBytes("professional data"));
  // deleting the data
  table.delete(delete);
  // closing the HTable object
  table.close();
  System.out.println("data deleted...");
 }
}

Scan Data Using java API
ScanTable.java

import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.util.Bytes;

public class ScanTable {
 @SuppressWarnings("deprecation")
 public static void main(String args[]) throws IOException {
  // Instantiating Configuration class
  Configuration config = HBaseConfiguration.create();
  // Instantiating HTable class
  HTable table = new HTable(config, "emp");
  // Instantiating the Scan class
  Scan scan = new Scan();
  // Scanning the required columns
  scan.addColumn(Bytes.toBytes("personal data"), Bytes.toBytes("name"));
  scan.addColumn(Bytes.toBytes("personal data"), Bytes.toBytes("city"));
  // Getting the scan result
  ResultScanner scanner = table.getScanner(scan);
  // Reading values from scan result
  for (Result result = scanner.next(); result != null; result = scanner
    .next())
   System.out.println("Found row : " + result);
  // closing the scanner
  scanner.close();
 }
}