Hibernate and JPA

Hibernate is an open-source, Object-Relational Mapping (ORM) framework for Java that simplifies the interaction between Java applications and relational databases. It provides a convenient way to map Java objects to database tables and perform database operations using Java method calls.

Java Persistence API (JPA) is a specification for managing relational data in Java applications. It provides a set of standard interfaces and annotations that developers can use to interact with databases using ORM frameworks like Hibernate.

To use Hibernate and JPA in your Java application, you need to:

1. Include Hibernate and JPA dependencies in your project's pom.xml file if you are using Maven or build.gradle file if you are using Gradle.

2. Configure the database connection in your application's configuration file, such as application.properties or application.yml.

3. Create an entity class that represents a database table. An entity class is annotated with @Entity and includes attributes that correspond to table columns.

4. Create a repository interface that extends JpaRepository or a similar interface provided by JPA. The repository interface includes standard CRUD methods and can also define custom query methods.

Here's an example of a Hibernate entity class and a repository interface:

1// Hibernate Entity Class
2
3import javax.persistence.Entity;
4import javax.persistence.GeneratedValue;
5import javax.persistence.GenerationType;
6import javax.persistence.Id;
7
8@Entity
9public class Product {
10
11    @Id
12    @GeneratedValue(strategy = GenerationType.IDENTITY)
13    private Long id;
14
15    private String name;
16    private double price;
17
18    // Constructor, getters, and setters
19
20}
21
22// Hibernate Repository Interface
23
24import org.springframework.data.jpa.repository.JpaRepository;
25
26public interface ProductRepository extends JpaRepository<Product, Long> {
27
28    // Custom query methods
29
30}

xxxxxxxxxx

}

```java

// Hibernate Entity Class

​

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

​

@Entity

public class Product {

​

    @Id

    @GeneratedValue(strategy = GenerationType.IDENTITY)

    private Long id;

​

    private String name;

    private double price;

​

    // Constructor, getters, and setters

​

}

​

// Hibernate Repository Interface

​

import org.springframework.data.jpa.repository.JpaRepository;

​

public interface ProductRepository extends JpaRepository<Product, Long> {

​

    // Custom query methods