Hibernate CRUD

Hibernate CRUD example

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="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernatedemo</property>
    <property name="hibernate.connection.username">root</property>
    <property name="hibernate.connection.password">123</property>
    <mapping class="entity.Student" />
  </session-factory>
</hibernate-configuration>

Student.java

package entity;

import java.io.Serializable;
import javax.persistence.*;


@Entity

public class Student implements Serializable {

    @Id
    @Column(name="id")
    private Integer id;
    @Column(name="name",length=100)
    private String username;
    @Column(name="email",length=100)
    private String email;

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }


}

HibernateUtil.java

package util;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;


public class HibernateUtil {

    private static final SessionFactory sessionFactory;

    static {
        try {
            sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
        } catch (Exception ex) {
            
            throw new ExceptionInInitializerError();
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }
}

AddStudentServlet.java

package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.hibernate.*;
import util.HibernateUtil;
import entity.*;


public class AddStudentServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        Session session = HibernateUtil.getSessionFactory().openSession();
        Transaction transaction = session.beginTransaction();

        Student student = new Student();
        student.setId(3);
        student.setUsername("sameera5");
        student.setEmail("jaya@yahoo.com5");

        session.save(student);
        transaction.commit();
        session.close();
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    }
}

UpdateStudentServlet.java

package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.hibernate.*;
import util.HibernateUtil;
import entity.Student;


public class UpdateStudentServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        Session session = HibernateUtil.getSessionFactory().openSession();
        Transaction transaction = session.beginTransaction();

        Student s = (Student) session.get(Student.class, new Integer(1));
        System.out.println(s.getUsername());
        if (s != null) {

            s.setEmail("sampatjhh");
            s.setUsername("sampath");
            session.update(s);
        }


        transaction.commit();
        session.close();


    }
}

ViewStudentServlet.java

package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.hibernate.*;
import util.HibernateUtil;
import entity.Student;
import java.util.List;


public class ViewStudentServlet extends HttpServlet {

  
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        PrintWriter out = response.getWriter();

        Session session = HibernateUtil.getSessionFactory().openSession();
        Transaction transaction = session.beginTransaction();

        Query query = session.createQuery("FROM Student");

        List<Student> students = query.list();

        for (Student student : students) {

            out.print(student.getUsername());

        }


        transaction.commit();
        session.close();
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /** 
     * Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /** 
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /** 
     * Returns a short description of the servlet.
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>
}

DeleteServlet.java

package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.hibernate.*;
import util.HibernateUtil;
import entity.Student;


public class DeleteServlet extends HttpServlet {
   

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        Session session = HibernateUtil.getSessionFactory().openSession();
        Transaction transaction = session.beginTransaction();

        Student s=(Student) session.get(Student.class, new Integer(1));
        System.out.println(s.getUsername());
        session.delete(s);
        transaction.commit();
        session.close();
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    }

}