Basic Annotations and HIbernate Example 1

hibernate.cfg.xml - Hibernate Configuration file

<?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">oracle.jdbc.driver.OracleDriver</property>

        <property name="connection.url">jdbc:oracle:thin:@172.16.7.236:20300:prtp</property>

        <property name="connection.username">MOBI_CLEANUP_TEST1</property>

        <property name="connection.password">MOBI_CLEANUP_TEST1</property>

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

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

      

           <property name="dialect">org.hibernate.dialect.Oracle9Dialect</property>

        <!-- Enable Hibernate's automatic session context management, by default its  update -->

       

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

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

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

              <mapping class="org.javadsalgo.dto.UserDetailsDTO"/>

              <!-- <mapping resource="org/javadsalgo/model/UserDetailsDTO.hbm.xml" /> -->

    </session-factory>

</hibernate-configuration>

UserDetailsDTO.java

package org.javadsalgo.dto;

@Entity(name = "USER_DETAILS")

public class UserDetailsDTO implements java.io.Serializable {

      private static final long serialVersionUID = 1L;

      @Id

      @GeneratedValue(strategy = GenerationType.AUTO)

      @Column(name = "USER_ID")

      private int userId;

      @Column(name = "USER_NAME")

      private String userName;

      @Temporal(TemporalType.DATE)

      private Date createdOn;

      private String Address;

      @Lob

      private String description;

      public Date getCreatedOn() {

            return createdOn;

      }

      public void setCreatedOn(Date createdOn) {

            this.createdOn = createdOn;

      }

      public String getAddress() {

            return Address;

      }

      public void setAddress(String address) {

            Address = address;

      }

      public String getDescription() {

            return description;

      }

      public void setDescription(String description) {

            description = description;

      }

      public int getUserId() {

            return userId;

      }

      public void setUserId(int userId) {

            this.userId = userId;

      }

      public String getUserName() {

            return userName;

      }

      public void setUserName(String userName) {

            this.userName = userName;

      }

}

It is important to note that each @Entity needs to be annotated with @Id which will be the primary key in table. If you don't want your entity to be persisted in a separate table, but rather be a part of other entities, you can use @Embeddable instead of @Entity.

If @Id is missing, it'll throw org.hibernate.AnnotationException: No identifier specified for entity 

HibernateTest.java

package org.javadsalgo.test;

import java.util.Date;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.Configuration;

import org.javadsalgo.dto.UserDetailsDTO;

public class HibernateTest {

      public static void main(String[] args) {

            UserDetailsDTO user =new UserDetailsDTO();

           

            //user.setUserId(1);

            user.setUserName("Abc");

            user.setAddress("722/18 Shastri Nagar , Rohtak");

            user.setCreatedOn(new Date());

            user.setDescription("Hey ,Hibernate is Amazing");

           

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

            Session session = sessionFactory.openSession();

            session.beginTransaction();

            session.save(user);

            session.getTransaction().commit();

            session.close();

           

            session = sessionFactory.openSession();

            session.beginTransaction();

            user=(UserDetailsDTO) session.get(UserDetailsDTO.class, 1);

            System.out.println("Name is "+user.getUserName()+"\nAddress             is  "+ user.getAddress());

            session.close();

           

      }

}

UserDetailsDTO.hbm.xml

<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

       <class name="org.javadsalgo.dto.UserDetailsDTO"

              table="USER_DETAILS_HBM">

              <composite-id>       

                     <key-property name ="userId" column = "USER_ID" />

              </composite-id>

              <property name="userName" column="USER_NAME" />

              <property name="createdOn" column="CREATED_ON" type="java.util.Date"/>

              <property name="description" column="DESCRIPTION" />         

       </class>

</hibernate-mapping>

Output :

Hibernate: select hibernate_sequence.nextval from dual

Hibernate: insert into USER_DETAILS (Address, createdOn, description, USER_NAME, USER_ID) values (?, ?, ?, ?, ?)

Hibernate: select userdetail0_.USER_ID as USER1_0_0_, userdetail0_.Address as Address0_0_, userdetail0_.createdOn as createdOn0_0_, userdetail0_.description as descript4_0_0_, userdetail0_.USER_NAME as USER5_0_0_ from USER_DETAILS userdetail0_ where userdetail0_.USER_ID=?

Name is Abc

Address is  722/18 Shastri Nagar , Rohtak