Basic HBase Java Classes and Methods – Part 3: Table Creation

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.foo</groupId>
    <artifactId>hbase-examples</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <repositories>
        <repository>
            <id>hbase-local</id>
            <name>Local HBase</name>
            <url>file:///Users/bfeeny/Documents/hbase/hbase-1.2.6/lib</url>
            <layout>default</layout>
        </repository>
    </repositories>

    <!-- https://mvnrepository.com/artifact/org.apache.hbase/hbase-client -->
    <dependencies>
        <dependency>
            <groupId>org.apache.hbase</groupId>
            <artifactId>hbase-client</artifactId>
            <version>1.2.6</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.apache.hadoop/hadoop-common -->
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-common</artifactId>
            <version>2.7.5</version>
        </dependency>
        <dependency>
            <groupId>org.apache.hbase</groupId>
            <artifactId>hbase-server</artifactId>
            <version>1.2.6</version>
        </dependency>
    </dependencies>
</project>

You may also want to optionally create a log4j.properties file if using Maven.  Maven uses this file for logging.  We will create a basic properties file and store it in our main/resources folder.  For more information on log4j visit the project site.  Here is the basic properties file we will use.

log4j.rootLogger=DEBUG, CA

log4j.appender.CA=org.apache.log4j.ConsoleAppender

log4j.appender.CA.layout=org.apache.log4j.PatternLayout
log4j.appender.CA.layout.ConversionPattern=%-4r <%t> %-5p %c %x - %m%nAdminCreateTable basic libraries and main method.

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.TableName;
import org.apache.hadoop.hbase.client.*;

import java.io.IOException;

public class AdminCreateTable {

    public static void main(String[] args) throws IOException {

    }
}Instantiating a Configuration object 

We will instantiate a Configuration object using the HBaseConfiguration static method.  The configuration Class is the base class for all config objects in the Hadoop ecosystem.

Configuration conf = HBaseConfiguration.create();Establish a connection to the HBase cluster

We use the ConnectionFactory to create a connection object by passing in our Configuration object.

Connection connection = ConnectionFactory.createConnection(conf);

All code which uses our connection should be in try / finally blocks so that you can manage the connection manually and close the connection when you are done using it.

Instantiate an Admin object

Because functions such as Creating or Removing tables are administrative functions, these must be done using the Admin object.  We will create an Admin object from our Connection object.

try {
    Admin admin = connection.getAdmin();
} finally {
    connection.close();
}
You can see we put the instantiation of the Admin object inside of our try/finally clause.  The rest of our commands will also be inside this clause.  We added a command to close our connection in the finally clause.

Create the table schema using an HTableDescriptor

We use an HTableDescriptor to define our table, its properties such as column families, performance settings, etc.  We will create a table of name employee and two column families: personal and professional.

TableDescriptor tableName = new HTableDescriptor(TableName.valueOf("employee"));

tableName.addFamily(new HColumnDescriptor("personal"));
tableName.addFamily(new HColumnDescriptor("professional"));
Create the table

We check to see if the table exists using our Admin object.  If it does not exist, we create it, and it does exist we print so.  We use the createTable method on our Admin object and pass in the HTableDescriptor we created previously.

if (!admin.tableExists(tableName.getTableName())) {
    System.out.print("Creating the employee table. ");

    admin.createTable(tableName);

    System.out.println("Done.");
} else {
    System.out.println("Table already exists");
}
Putting it all together we have the following:

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.TableName;
import org.apache.hadoop.hbase.client.*;

import java.io.IOException;

public class AdminCreateTable {

    public static void main(String[] args) throws IOException {

        Configuration conf = HBaseConfiguration.create();
        Connection connection = ConnectionFactory.createConnection(conf);

        try {
            Admin admin = connection.getAdmin();

            HTableDescriptor tableName = new HTableDescriptor(TableName.valueOf("employee"));

            tableName.addFamily(new HColumnDescriptor("personal"));
            tableName.addFamily(new HColumnDescriptor("professional"));

            if (!admin.tableExists(tableName.getTableName())) {
                System.out.print("Creating the employee table. ");

                admin.createTable(tableName);

                System.out.println("Done.");
            } else {
                System.out.println("Table already exists");
            }
        } finally {
            connection.close();
        }
    }
}
Build and Run the code. You can verify the table has been created by going to the HBase Shell and verifying it exists.

Brian-Feenys-Mac-Pro:hbase-examples bfeeny$ hbase shell
2018-03-11 20:55:32,254 WARN   util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in 
SLF4J: Found binding in 
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type 
HBase Shell; enter 'help<RETURN>' for list of supported commands.
Type "exit<RETURN>" to leave the HBase Shell
Version 1.2.6, rUnknown, Mon May 29 02:25:32 CDT 2017

hbase(main):001:0> list
TABLE                                                                                                                                                                            
employee                                                                                                                                                                         
1 row(s) in 0.1720 seconds

=> ["employee"]
hbase(main):002:0> describe 'employee'
Table employee is ENABLED                                                                                                                                                        
employee                                                                                                                                                                         
COLUMN FAMILIES DESCRIPTION                                                                                                                                                      
{NAME => 'personal', BLOOMFILTER => 'ROW', VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE', DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESSION => 
'NONE', MIN_VERSIONS => '0', BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE => '0'}                                                                               
{NAME => 'professional', BLOOMFILTER => 'ROW', VERSIONS => '1', IN_MEMORY => 'false', KEEP_DELETED_CELLS => 'FALSE', DATA_BLOCK_ENCODING => 'NONE', TTL => 'FOREVER', COMPRESSION
 => 'NONE', MIN_VERSIONS => '0', BLOCKCACHE => 'true', BLOCKSIZE => '65536', REPLICATION_SCOPE => '0'}                                                                           
2 row(s) in 0.0960 seconds

hbase(main):003:0> 

See you in the next part Basic HBase Java Classes and Methods – Part 4: Putting Data into a Table