Hibernate CRUD Operations using Annotations with Maven and Eclipse

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This tutorial shows how to create a step by step Hibernate application to perform CRUD operations against the database. In this example, we use Eclipse IDE, Maven as project management and build tool and MySQL as a database.

We also use Hibernate Java-based configuration and JPA annotations to create a JPA entity.

Video Tutorial

This tutorial is explained in below YouTube video. Subscribe to my youtube channel to learn more about Spring boot at Java Guides - YouTube Channel.

Technologies and tools used

• Hibernate 5.3.7.Final
• IDE - Eclipse Noen
• Maven 3.5.3
• JavaSE 1.8
• MySQL - 8.0.13

Development Steps

1. Create a Simple Maven Project
2. Project Directory Structure
3. Add jar Dependencies to pom.xml
4. Creating the JPA Entity Class(Persistent class)
5. Create a Hibernate configuration file - Java Configuration
6. Create a Student class
7. Create the Main class and Run an Application

Let's start developing step by step Hibernate application in Eclipse using Maven as project management and build tool.

1. Create a Simple Maven Project

Use How to Create a Simple Maven Project in Eclipse article to create a simple Maven project in Eclipse IDE.

2. Project Directory Structure

The project directory structure for your reference -

3. Add jar Dependencies to pom.xml

Let's add MySQL and hibernate-core dependencies to below pom.xml:

<project
    xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>net.javaguides</groupId>
    <artifactId>hibernate-crud-example</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>Hibernate CRUD Example</name>
    <description>Hibernate CRUD Example</description>
    <dependencies>
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.13</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.3.7.Final</version>
        </dependency>
    </dependencies>
</project>

4. Creating the JPA Entity Class(Persistent class)

Let's create a Student persistent class that is mapped to a student database table:

A simple Persistent class should follow some rules:

• A no-arg constructor: It is recommended that you have a default constructor at least package visibility so that hibernate can create the instance of the Persistent class by newInstance() method.
• Provide an identifier property: It is better to assign an attribute as id. This attribute behaves as a primary key in a database.
• Declare getter and setter methods: The Hibernate recognizes the method by getter and setter method names by default.
• Prefer non-final class: Hibernate uses the concept of proxies, which depends on the persistent class. The application programmer will not be able to use proxies for lazy association fetching.

Create a Student entity class under net.javaguides.hibernate.entity package as follows.

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

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

    @Id
    @GeneratedValue(strategy = GenerationType.Auto)
    @Column(name = "id")
    private int id;

    @Column(name = "first_name")
    private String firstName;

    @Column(name = "last_name")
    private String lastName;

    @Column(name = "email")
    private String email;

    public Student() {

    }

    public Student(String firstName, String lastName, String email) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }

    public int getId() {
        return id;
    }

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

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getEmail() {
        return email;
    }

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

    @Override
    public String toString() {
        return "Student [id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + ", email=" + email + "]";
    }
}

5. Create a Hibernate configuration file - Java Configuration

The HibernateUtil Java configuration file contains information about the database and mapping file.

Let's create a HibernateUtil file and write the following code in it.

package net.javaguides.hibernate.util;

import java.util.Properties;

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.cfg.Environment;
import org.hibernate.service.ServiceRegistry;

import net.javaguides.hibernate.model.Student;

public class HibernateUtil {
    private static SessionFactory sessionFactory;
    public static SessionFactory getSessionFactory() {
        if (sessionFactory == null) {
            try {
                Configuration configuration = new Configuration();

                // Hibernate settings equivalent to hibernate.cfg.xml's properties
                Properties settings = new Properties();
                settings.put(Environment.DRIVER, "com.mysql.cj.jdbc.Driver");
                settings.put(Environment.URL, "jdbc:mysql://localhost:3306/hibernate_db?useSSL=false");
                settings.put(Environment.USER, "root");
                settings.put(Environment.PASS, "root");
                settings.put(Environment.DIALECT, "org.hibernate.dialect.MySQL5Dialect");

                settings.put(Environment.SHOW_SQL, "true");

                settings.put(Environment.CURRENT_SESSION_CONTEXT_CLASS, "thread");

                settings.put(Environment.HBM2DDL_AUTO, "create-drop");

                configuration.setProperties(settings);

                configuration.addAnnotatedClass(Student.class);

                ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
                    .applySettings(configuration.getProperties()).build();

                sessionFactory = configuration.buildSessionFactory(serviceRegistry);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return sessionFactory;
    }
}

6. Create IStudentDao Interface and StudentDao Impl Class

Let's create a separate IStudentDao interface with the following methods:

package net.javaguides.hibernate.dao;

import java.util.List;

import net.javaguides.hibernate.model.Student;

public interface IStudentDao {

 void saveStudent(Student student);

 void updateStudent(Student student);

 Student getStudentById(long id);

 List<Student> getAllStudents();

 void deleteStudent(long id);

}

Let's create StudentDao class which implements the above IStudentDao interface:

package net.javaguides.hibernate.dao;

import java.util.List;

import javax.transaction.Transactional;

import org.hibernate.Session;
import org.hibernate.Transaction;

import net.javaguides.hibernate.model.Student;
import net.javaguides.hibernate.util.HibernateUtil;

public class StudentDao implements IStudentDao {

    // save Student
    // get All Students
    // get Student By Id
    // Update Student
    // Delete Student

    /* (non-Javadoc)
     * @see net.javaguides.hibernate.dao.IStudentDao#saveStudent(net.javaguides.hibernate.model.Student)
     */
    @Override
    public void saveStudent(Student student) {
        Transaction transaction = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start the transaction
            transaction = session.beginTransaction();

            // save student object
            session.save(student);

            // commit the transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
        }
    }

    /* (non-Javadoc)
     * @see net.javaguides.hibernate.dao.IStudentDao#updateStudent(net.javaguides.hibernate.model.Student)
     */
    @Override
    public void updateStudent(Student student) {
        Transaction transaction = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start the transaction
            transaction = session.beginTransaction();

            // save student object
            session.saveOrUpdate(student);

            // commit the transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
        }
    }

    /* (non-Javadoc)
     * @see net.javaguides.hibernate.dao.IStudentDao#getStudentById(long)
     */
    @Override
    public Student getStudentById(long id) {
        Transaction transaction = null;
        Student student = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start the transaction
            transaction = session.beginTransaction();

            // get student object
            student = session.get(Student.class, id);
            //student = session.load(Student.class, id);
            // commit the transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
        }
        return student;
    }

    /* (non-Javadoc)
     * @see net.javaguides.hibernate.dao.IStudentDao#getAllStudents()
     */
    @Override
    @SuppressWarnings("unchecked")
    public List < Student > getAllStudents() {
        Transaction transaction = null;
        List < Student > students = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start the transaction
            transaction = session.beginTransaction();

            // get students
            students = session.createQuery("from Student").list();
            //student = session.load(Student.class, id);
            // commit the transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
        }
        return students;
    }

    /* (non-Javadoc)
     * @see net.javaguides.hibernate.dao.IStudentDao#deleteStudent(long)
     */
    @Override
    public void deleteStudent(long id) {
        Transaction transaction = null;
        Student student = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start the transaction
            transaction = session.beginTransaction();

            student = session.get(Student.class, id);
            // get student object
            session.delete(student);
            //student = session.load(Student.class, id);
            // commit the transaction
            transaction.commit();
        } catch (Exception e) {
            if (transaction != null) {
                transaction.rollback();
            }
        }
    }
}

7. Create the Main App class and Run an Application

Let's test the Hibernate application to connect the MySQL database with CRUD operations:

package net.javaguides.hibernate;

import java.util.List;

import net.javaguides.hibernate.dao.IStudentDao;
import net.javaguides.hibernate.dao.StudentDao;
import net.javaguides.hibernate.model.Student;

public class App {

    public static void main(String[] args) {

        IStudentDao studentDao = new StudentDao();

        // test saveStudent
        Student student = new Student("Ramesh", "Fadatare", "ramesh@gmail.com");
        studentDao.saveStudent(student);

        // test updateStudent
        student.setFirstName("Ram");
        studentDao.updateStudent(student);

        // test getStudentById
        Student student2 = studentDao.getStudentById(student.getId());

        // test getAllStudents
        List < Student > students = studentDao.getAllStudents();
        students.forEach(student1 - > System.out.println(student1.getId()));

        // test deleteStudent
        studentDao.deleteStudent(student.getId());

    }
}

Once you run this class will produce below output in console:

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