03 - Part-3-Saving-Objects-using-Hibernate-APIs

Using the Hibernate API

* Create a session factory

                It is one object per application.

                It creates session, how sessions you want in your application.

* Create a session from the session factory (to save / retrieve data from database).

* Use the session to save the model object.

hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>

<!DOCTYPE hibernate-configuration PUBLIC

        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"

        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>

        <property name="connection.driver_class">

org.postgresql.Driver

        </property>

        <property name="connection.url">

            jdbc:postgresql://localhost:5433/hibernatedb

  </property>

        <property name="connection.username">postgres</property>

        <property name="connection.password">admin</property>

        <!-- JDBC connection pool (use the built-in) -->

        <property name="connection.pool_size">1</property>

        <!-- SQL dialect -->

        <property name="dialect">

            org.hibernate.dialect.PostgreSQLDialect

        </property>

        <!-- Enable Hibernate's automatic session context management -->

        <property name="current_session_context_class">thread</property>

       

        <!-- Echo all executed SQL to stdout -->

        <property name="show_sql">true</property>

       

        <!-- Drop and re-create the database schema on startup -->

            <property name="hbm2ddl.auto">create</property> 

   

          <!-- Names the annotated entity class -->

            <mapping class="org.yash.dto.UserDetails"/>    

    </session-factory>

</hibernate-configuration>

UserDetails.java

package org.yash.dto;

import javax.persistence.Entity;

import javax.persistence.Id;

@Entity

public class UserDetails {

      @Id

      private int userId;

      private String userName;

      public void setUserId(int userId) {

            this.userId = userId;

      }

      public int getUserId() {

            return userId;

      }

      public void setUserName(String userName) {

            this.userName = userName;

      }

      public String getUserName() {

            return userName;

      }

}

HibernateTest.java

package org.yash.hibernate;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.Configuration;

import org.yash.dto.UserDetails;

public class HibernateTest {

      public static void main(String args[]){

            UserDetails user = new UserDetails();

            user.setUserId(1);

            user.setUserName("First User");

           

            SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();

           

            Session session = sessionFactory.openSession();

            /* It is used to save all the objects and to define single unit of work */

            session.beginTransaction();

           

            session.save(user);

            session.getTransaction().commit();

      }

}