Session 3 - hibernate - Configuration with Annotations.pptx

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1. HIBERNATE CONFIGURATION WITH ANNOTAION

2. Hibernate Configuration with Annotations Hibernate is an Object-Relational Mapping (ORM) framework for Java Allows you to map Java objects to database tables and vice versa. When using Hibernate with annotations, you can configure the mapping between your Java classes and the database tables without the need for XML configuration files.

3. Step-by-step Guide To Configuring Hibernate Using Annotations: Set up the Hibernate dependencies: Make sure you have the necessary Hibernate dependencies in your project . This typically includes the Hibernate core library, the appropriate database driver for your database, and the Java Persistence API (JPA) libraries. Configure the Hibernate properties : Create a properties file (e.g., hibernate.properties ) or a configuration class to set up the Hibernate properties

4. Example using properties file # Database connection properties hibernate.connection.driver_class = your.database.driver.Class hibernate.connection.url = jdbc:mysql ://localhost:3306/ your_database hibernate.connection.username = your_username hibernate.connection.password = your_password # Hibernate properties hibernate.dialect = org.hibernate.dialect.MySQLDialect hibernate.hbm2ddl.auto = update

5. 3. Create the Hibernate configuration class: You can create a configuration class that will initialize the Hibernate configuration using the annotations. Here's an example of a configuration class:

6. import org.hibernate.cfg.Configuration ; public class HibernateConfig { private static SessionFactory sessionFactory ; public static SessionFactory getSessionFactory () { if ( sessionFactory == null) { try { // Create a Configuration instance Configuration configuration = new Configuration(); // Configure Hibernate using the properties file configuration.configure (" hibernate.properties "); // Add annotated classes configuration.addAnnotatedClass (YourEntityClass1.class); configuration.addAnnotatedClass (YourEntityClass2.class); // Add other entity classes as needed // Build the SessionFactory sessionFactory = configuration.buildSessionFactory (); } catch ( Throwable ex) { System.err.println (" SessionFactory creation failed." + ex); throw new ExceptionInInitializerError (ex); } } return sessionFactory ; } }

7. 4. Define your entity classes: Create your entity classes, which represent your database tables. Annotate them with Hibernate annotations to define the mapping between the classes and the database tables Example follows:

8. Example import javax.persistence.Entity ; import javax.persistence.GeneratedValue ; import javax.persistence.GenerationType ; import javax.persistence.Id ; @Entity public class YourEntityClass { @Id @ GeneratedValue (strategy = GenerationType.IDENTITY ) private Long id; // Other properties and getters/setters }

9. 5. Perform database operations: You can now use the SessionFactory to create Session instances And perform database operations . Example Follows :

10. import org.hibernate.Session ; import org.hibernate.Transaction ; public class Main { public static void main(String[] args ) { SessionFactory sessionFactory = HibernateConfig.getSessionFactory (); Session session = sessionFactory.openSession (); try { Transaction transaction = session.beginTransaction (); // Perform database operations YourEntityClass entity = new YourEntityClass (); entity.setProperty ("value"); session.save (entity); transaction.commit (); } catch (Exception e) { e.printStackTrace (); } finally { session.close (); sessionFactory.close (); } } }