Main class for hibernate 4 example

MainClass.java

package com.cc.example.hibernate;
import java.util.Iterator;
import java.util.List;

import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;

public class MainClass {
  
private static ServiceRegistry serviceRegistry;
private static SessionFactory sessionFactory;

public static void main(String[] args) {
  try{
    // This step will read hibernate.cfg.xml and prepare hibernate for use
    Configuration cfg=new Configuration().configure();
    serviceRegistry = new ServiceRegistryBuilder().applySettings(
    cfg.getProperties()).buildServiceRegistry();
    sessionFactory = cfg.buildSessionFactory(serviceRegistry);
    //Create employee objects to be persisted
    Employee emp1=new Employee(1,"Sourabh","Soni","[email protected]");
    Employee emp2=new Employee(2,"test","User1","[email protected]");
    Employee emp3=new Employee(3,"test","User2","[email protected]");
    
    //Create a handler to access methods
    MainClass handler=new MainClass()  
    //insert records
    handler.insert_record(emp1);
    handler.insert_record(emp2);
    handler.insert_record(emp3); 
    //Retrieve these records
    handler.getAllEmployees();
    //Update a record
    handler.updateEmployee(2, "[email protected]");
    //Check if the record is updated
    handler.getEmployee(2); 
  }catch(Exception e){
    System.out.println(e.getMessage());
  }finally{
    // Actual contact insertion will happen at this step
  }
}

public void insert_record(Employee emp)
{
  Session session=null;
  Transaction tx=null;
  try
  {
    session =sessionFactory.openSession();
    tx=session.getTransaction();
    tx.begin();
    session.save(emp);
    tx.commit();
    session.flush();
  }catch(HibernateException he){
    if(tx!=null)tx.rollback();
    System.out.println("Not able to open session");
    he.printStackTrace();
  }
  catch(Exception e){
    e.printStackTrace();
  }finally{
    if(session!=null)
    session.close();
  }
}

public void getEmployee(long id)
{
  Session session=null;
  Transaction tx=null;
  try
  {
    session=sessionFactory.openSession();
    tx=session.beginTransaction();
    Employee emp=(Employee)session.get(Employee.class, id);
    System.out.println("Name:"+emp.getFirstName()+" "+emp.getLastName());
    System.out.println("Email:"+emp.getEmail());
    tx.commit();
  }catch(HibernateException he){
    if(tx!=null)tx.rollback();
    he.printStackTrace();
  }finally{
    if(session!=null)
    session.close();
  }
}
public void getAllEmployees()
{
  Session session=null;
  Transaction tx=null;
  try
  {
    session=sessionFactory.openSession();
    tx=session.beginTransaction();
    String SQL_Query="FROM Employee";
    Query query=session.createQuery(SQL_Query);
    List employees=query.list();
    Iterator itr=employees.iterator();
    while(itr.hasNext())
    {
      Employee emp=(Employee)itr.next();
      System.out.println("Employee id:"+emp.getId());
      System.out.println("Name:"+emp.getFirstName()+" "+emp.getLastName());
      System.out.println("Email:"+emp.getEmail());
    }
    tx.commit();
  }catch(HibernateException he){
    if(tx!=null)tx.rollback();
    he.printStackTrace();
  }finally{
    if(session!=null)
    session.close();
  }
}

public void updateEmployee(long id,String email)
{
  Session session=null;
  Transaction tx=null;
  try
  {
    session=sessionFactory.openSession();
    tx=session.beginTransaction();
    Employee emp=(Employee)session.get(Employee.class, id);
    emp.setEmail(email);
    session.update(emp);
    tx.commit();
  }catch(HibernateException he){
    if(tx!=null)tx.rollback();
    he.printStackTrace();
  }finally{
    if(session!=null)
    session.close();
  }
}

}