Hibernate With Annotations

• Data about data is called Meta Data
• Configuring resources to pass their details to underlying software where the resources will be utilized for execution also comes under meta data operations
• 
  

• In earlier days programmers have taken the support of XML files for resources configurations and for meta data operations
• In recent days we can also use the java statements called annotations as alternative for XML files based application.
• XML files gives flexibility towards modifications but it does not give good performance because reading data from XML files is always quite complex operations
• Annotations gives good performance but doesn't provide flexibility towards modifications
• If Annotations & XML files both are configured for meta data operations then the setting done in XML file will be effected.
• We can apply annotations at three levels
• Resource Level
• Field Level
• Method Level   
• We will see Basic application for Hibernate Annotations (Resources for this)
• Table in Database
• POJO class
• hibernate configurations file
• client applications
• Table in database
• create table std (stdno number(3),stdname varchar(10),stdadd varchar(10));

• std.java(POJO class with Annatations)

import java.io.Serializable;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.Id;

import javax.persistence.Table;

@Entity

@Table(name = "std")

/* Here Entity describe for class to table relations*/

public class Std implements Serializable {/*@Id is id Generator  for coloumn*/

@Id

 @Column(name = "stdno")

private int stdno;

           /* column mapping*/

@Column(name = "stdname")

private String stdname;

        /* column mapping*/ 

@Column(name="stdadd")

private String stdadd;

public int getStdno() {

return stdno;

}

public void setStdno(int stdno) {

this.stdno = stdno;

}

public String getStdname() {

return stdname;

}

public void setStdname(String stdname) {

this.stdname = stdname;

}

public String getStdadd() {

return stdadd;

}

public void setStdadd(String stdadd) {

this.stdadd = stdadd;

}

}

hibernate.cfg.xml

<?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://localhost/abc</property>

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

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

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

<mapping class="Std"/>

</session-factory>

</hibernate-configuration>

client.java

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.Configuration;

public class Client {

public static void main(String[] args) {

// TODO Auto-generated method stub

Configuration cfg=new Configuration();

cfg.configure();

SessionFactory sf=cfg.buildSessionFactory();

Session s=sf.openSession();

Std obj=new Std();

obj.setStdno(10);

obj.setStdname("abc");

obj.setStdadd("abcom");

s.save(obj);

Transaction t=s.beginTransaction();

t.commit();

}

}

For Downloading above project with library files