Hibernate Annotation Example

Annotation is used to change the behavior of a class, method, and data member of the class using a predefined attribute.
Without using the hibernate mapping file we can map the database table using an annotation class.
The annotation will be defined under the POJO Class.
@Table:-  this annotation is used to map the database table from class
@Column:-  this annotation is used to map the database table column
@id:-   it is used to define the primary key column of the table
@Entity:-  It is used to provide annotation to implement database schema
if we use the Annotation Mapping class then we will define the mapping class under the hibernate.cfg.xml file

<mapping class="packagename.Pojoclassname" />
All hibernate annotations exist under javax.persistent package. means javax.persistence jar file should be present in your project lib folder.

Step First:-

Create Pojo class with annotation

package scs;

import javax.persistence.*;

@Entity

@Table(name="tbl_student")

public class Student {

@Id

private int rno;

@Column

private String sname;

@Column

private String branch;

@Column

private int fees;

public int getRno() {

return rno;

}

public void setRno(int rno) {

this.rno = rno;

}

public String getSname() {

return sname;

}

public void setSname(String sname) {

this.sname = sname;

}

public String getBranch() {

return branch;

}

public void setBranch(String branch) {

this.branch = branch;

}

public int getFees() {

return fees;

}

public void setFees(int fees) {

this.fees = fees;

}

}

Step2nd:-

Create hibernate.cfg.xml file and add POJO class as a mapping file reference

<!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">com.mysql.jdbc.Driver</property>

<property name="connection.url">jdbc:mysql://localhost:3306/java56db</property>

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

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

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

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

 <mapping class="scs.Student"></mapping>

</session-factory>

</hibernate-configuration>

Step4th:-

Create Datahelper class:-

package dao;

import java.util.List;

import org.hibernate.*;

import org.hibernate.cfg.*;

public class DataHelper {

static SessionFactory sf ;

static Session s ;

public static void connection()

{

Configuration cfg = new Configuration();

cfg.configure("hibernate.cfg.xml");

sf= cfg.buildSessionFactory();

s = sf.openSession();

}

public static List dqlOperation(String query)

{

Query q = s.createQuery(query);

return q.list();

}

public static void dmlOperation(Object c)

{

Transaction tx = s.beginTransaction();

s.save(c);

    tx.commit();    

}

public static void deleteOperation(Object c)

{

Transaction tx = s.beginTransaction();

s.delete(c);

    tx.commit();

   }

public static Object findOperation(Class c,int id)

{

return s.load(c,id);

}

public static void closeConn()

{

s.close();

sf.close();

} 

}

Step3rd:-

Write the code to Insert the record

package scs;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.*;

import dao.DataHelper;

public class InsertRecord {

public static void main(String[] args) {

DataHelper.connection();

Student stu = new Student();

stu.setRno(1007);

stu.setSname("XYZ");

stu.setBranch("IT");

stu.setFees(350000);

DataHelper.dmlOperation(stu);

DataHelper.closeConn();

}

}