Hibernate - Create, Read, Update and Delete (CRUD) Operations Example

In this tutorial, we will demonstrate how to perform basic CRUD (Create, Read, Update, and Delete) operations using Hibernate framework 6 with a Book entity.

Prerequisites

Before we start, ensure you have the following:

• Java Development Kit (JDK) installed
• Apache Maven installed
• MySQL database installed and running (or any other relational database)
• An IDE (such as IntelliJ IDEA, Eclipse, or VS Code) installed

Step 1: Setting Up the Project

1.1 Create a Maven Project

1. Open your IDE and create a new Maven project.

2. Configure the pom.xml file with the following content:

<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>com.example</groupId>
    <artifactId>hibernate-crud-example</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- Hibernate and JPA -->
        <dependency>
            <groupId>org.hibernate.orm</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>6.4.0.Final</version>
        </dependency>
        <dependency>
            <groupId>jakarta.persistence</groupId>
            <artifactId>jakarta.persistence-api</artifactId>
            <version>3.1.0</version>
        </dependency>

        <!-- MySQL Connector -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.26</version>
        </dependency>

        <!-- SLF4J for logging -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.32</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.32</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>17</source>
                    <target>17</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

1.2 Configure Hibernate

Create a persistence.xml file in the src/main/resources/META-INF directory with the following content:

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="https://jakarta.ee/xml/ns/persistence" version="3.0">
    <persistence-unit name="examplePU">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <class>com.example.hibernatecrud.model.Book</class>
        <properties>
            <property name="jakarta.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/your_database_name"/>
            <property name="jakarta.persistence.jdbc.user" value="your_username"/>
            <property name="jakarta.persistence.jdbc.password" value="your_password"/>
            <property name="jakarta.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver"/>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
            <property name="hibernate.hbm2ddl.auto" value="update"/>
            <property name="hibernate.show_sql" value="true"/>
            <property name="hibernate.format_sql" value="true"/>
        </properties>
    </persistence-unit>
</persistence>

Replace your_database_name, your_username, and your_password with your MySQL database credentials.

Step 2: Creating the Entity Class

Create a Book class in the com.example.hibernatecrud.model package:

package com.example.hibernatecrud.model;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;

@Entity
public class Book {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String title;
    private String author;
    private double price;

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

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

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }
}

Step 3: Creating the DAO Class

Create a DAO class to manage CRUD operations in the com.example.hibernatecrud.dao package:

package com.example.hibernatecrud.dao;

import com.example.hibernatecrud.model.Book;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.TypedQuery;
import java.util.List;

public class BookDao {

    private EntityManagerFactory emf = Persistence.createEntityManagerFactory("examplePU");

    public void saveBook(Book book) {
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        em.persist(book);
        em.getTransaction().commit();
        em.close();
    }

    public void updateBook(Book book) {
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        em.merge(book);
        em.getTransaction().commit();
        em.close();
    }

    public Book getBookById(Long id) {
        EntityManager em = emf.createEntityManager();
        Book book = em.find(Book.class, id);
        em.close();
        return book;
    }

    public List<Book> getAllBooks() {
        EntityManager em = emf.createEntityManager();
        TypedQuery<Book> query = em.createQuery("SELECT b FROM Book b", Book.class);
        List<Book> books = query.getResultList();
        em.close();
        return books;
    }

    public void deleteBook(Long id) {
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        Book book = em.find(Book.class, id);
        if (book != null) {
            em.remove(book);
        }
        em.getTransaction().commit();
        em.close();
    }
}

Step 4: Creating the Main Class

Create a Main class in the com.example.hibernatecrud package to test the CRUD operations:

package com.example.hibernatecrud;

import com.example.hibernatecrud.dao.BookDao;
import com.example.hibernatecrud.model.Book;

import java.util.List;

public class Main {
    public static void main(String[] args) {
        BookDao bookDao = new BookDao();

        // Create and save a new book
        Book book = new Book();
        book.setTitle("Hibernate in Action");
        book.setAuthor("Gavin King");
        book.setPrice(49.99);
        bookDao.saveBook(book);
        System.out.println("Book saved.");

        // Fetch and print all books
        List<Book> books = bookDao.getAllBooks();
        books.forEach(b -> System.out.println(b.getTitle() + " - " + b.getAuthor() + " - " + b.getPrice()));

        // Update a book
        book.setPrice(39.99);
        bookDao.updateBook(book);
        System.out.println("Book updated.");

        // Fetch and print the updated book
        Book updatedBook = bookDao.getBookById(book.getId());
        System.out.println("Updated Book: " + updatedBook.getTitle() + " - " + updatedBook.getAuthor() + " - " + updatedBook.getPrice());

        // Delete a book
        bookDao.deleteBook(updatedBook.getId());
        System.out.println("Book deleted.");
    }
}

Conclusion

In this tutorial, we demonstrated how to perform basic CRUD operations using Hibernate 6.4 with a Book entity. We configured the project with Maven, set up Hibernate and JPA, created an entity class, a DAO class, and a main class to test the CRUD operations. By following these steps, you can effectively manage data persistence in your Java applications using Hibernate and JPA.