Hibernate Configuration
The configuration of Hibernate is handled by the instance of org.hibernate.cfg.Configuration . It symbolizes the complete mapping between Java data types to the SQL database or database table. It is used to construct org.hibernate.SessionFactory . Various XML mapping files or Java Annotations compilation build these mapping.
Following 3 types of configuration is provided by the Hibernate :
(1) hibernate.cfg.xml
This XML file resides in root of application's CLASSPATH. This file constitutes hibernate configuration.
A sample hibernate.cfg.xml file is given below :
<?xml version='1.0' encoding='utf-8'?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql://192.168.10.13:3306/ankdb</property> <property name="hibernate.connection.username">root</property> <property name="hibernate.connection.password">root</property> <property name="hibernate.connection.pool_size">10</property> <property name="show_sql">true</property> <property name="dialect">org.hibernate.dialect.MySQLDialect</property> <property name="hibernate.current_session_context_class">thread</property> <mapping class="worker.Worker" /> </session-factory> </hibernate-configuration>
(2) hibernate.properties
This property file contains the key-value pair for different hibernate configuration.
The sample hibernate.properties file is given below :
hibernate.connection.driver_class=com.mysql.jdbc.Driver hibernate.connection.url= jdbc:mysql://192.168.10.13:3306/ankdb hibernate.connection.username=root hibernate.connection.password=root hibernate.connection.pool_size=1 hibernate.transaction.factory_class = \ org.hibernate.transaction.JTATransactionFactory hibernate.transaction.manager_lookup_class = \ org.hibernate.transaction.JBossTransactionManagerLookup hibernate.dialect = org.hibernate.dialect.MySQLDialect
(3) Programmatic configuration
This is the manual configuration which needs to be done in Java file. We can get an instance of org.hibernate.cfg.Configuration directly by specifying mapped class using .addClass( ).
Configuration cfg = new Configuration() .addClass(worker.Worker.class) .addClass(worker.Department.class);
Building a SessionFactory
After creating instance of org.hibernate.cfg.Configuration , you can create instance of SessionFactory as follows:
SessionFactory sessions = cfg.buildSessionFactory();
Creating Session instance
Between database table and application, Session represents a communication channel. From SessionFactory , Session can be created as follows:
Session session = sessions.openSession();