Spring ORM Example using Hibernate

package com.example.model;

import jakarta.persistence.*;

@Entity
@Table(name = "students")
public class Student {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "name", nullable = false)
    private String name;

    @Column(name = "email", unique = true)
    private String email;

    // Getters and Setters
    public Long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

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

package com.example.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.orm.hibernate5.LocalSessionFactoryBean;
import org.springframework.orm.hibernate5.HibernateTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import javax.sql.DataSource;
import java.util.Properties;

@Configuration
@EnableTransactionManagement
public class HibernateConfig {

    @Bean
    public LocalSessionFactoryBean sessionFactory() {
        LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
        sessionFactory.setDataSource(dataSource());
        sessionFactory.setPackagesToScan("com.example.model");
        sessionFactory.setHibernateProperties(hibernateProperties());
        return sessionFactory;
    }

    @Bean
    public DataSource dataSource() {
        org.springframework.jdbc.datasource.DriverManagerDataSource dataSource = new org.springframework.jdbc.datasource.DriverManagerDataSource();
        dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost:3306/mydb");
        dataSource.setUsername("root");
        dataSource.setPassword("password");
        return dataSource;
    }

    private Properties hibernateProperties() {
        Properties properties = new Properties();
        properties.put("hibernate.dialect", "org.hibernate.dialect.MySQL8Dialect");
        properties.put("hibernate.show_sql", "true");
        properties.put("hibernate.hbm2ddl.auto", "update");
        return properties;
    }

    @Bean
    public HibernateTransactionManager transactionManager() {
        HibernateTransactionManager txManager = new HibernateTransactionManager();
        txManager.setSessionFactory(sessionFactory().getObject());
        return txManager;
    }
}

package com.example.dao;

import com.example.model.Student;
import java.util.List;

public interface StudentDao {
    void save(Student student);
    Student findById(Long id);
    List<Student> findAll();
    void update(Student student);
    void delete(Long id);
}

package com.example.dao;

import com.example.model.Student;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;

@Repository
@Transactional
public class StudentDaoImpl implements StudentDao {

    @Autowired
    private SessionFactory sessionFactory;

    @Override
    public void save(Student student) {
        Session session = sessionFactory.getCurrentSession();
        session.save(student);
    }

    @Override
    public Student findById(Long id) {
        Session session = sessionFactory.getCurrentSession();
        return session.get(Student.class, id);
    }

    @Override
    public List<Student> findAll() {
        Session session = sessionFactory.getCurrentSession();
        return session.createQuery("FROM Student", Student.class).getResultList();
    }

    @Override
    public void update(Student student) {
        Session session = sessionFactory.getCurrentSession();
        session.update(student);
    }

    @Override
    public void delete(Long id) {
        Session session = sessionFactory.getCurrentSession();
        Student student = session.get(Student.class, id);
        if (student != null) {
            session.delete(student);
        }
    }
}

package com.example;

import com.example.config.HibernateConfig;
import com.example.dao.StudentDao;
import com.example.model.Student;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

import java.util.List;

public class MainApp {
    public static void main(String[] args) {
        // Initialize Spring context
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(HibernateConfig.class);
        StudentDao studentDao = context.getBean(StudentDao.class);

        // Insert a new student with ID 101 and name "Nisha"
        Student student1 = new Student();
         // Manually set ID for demonstration
        student1.setId(101L);
        student1.setName("Nisha");
        studentDao.save(student1);
        System.out.println("Student inserted: " + student1);

        // Update the student's name to "Priya"
        student1.setName("Priya");
        studentDao.update(student1);
        System.out.println("Student updated: " + student1);

        // Retrieve the student with ID 101
        Student retrievedStudent = studentDao.findById(101L);
        System.out.println("Retrieved Student: " + retrievedStudent);

        // Insert additional students for demonstration
        Student student2 = new Student();
         // Manually set ID for demonstration
        student2.setId(102L);
        student2.setName("Danish");
        studentDao.save(student2);

        Student student3 = new Student();
        // Manually set ID for demonstration
        student3.setId(103L); 
        student3.setName("Sneha");
        studentDao.save(student3);

        // Retrieve all students before deletion
        System.out.println("All Students Before Deletion:");
        List<Student> studentsBeforeDeletion = studentDao.findAll();
        studentsBeforeDeletion.forEach(System.out::println);

        // Delete the student with ID 102
        studentDao.delete(102L);
        System.out.println("Student with ID 102 deleted.");

        // Retrieve all students after deletion
        System.out.println("All Students After Deletion:");
        List<Student> studentsAfterDeletion = studentDao.findAll();
        studentsAfterDeletion.forEach(System.out::println);

        // Close the Spring context
        context.close();
    }
}