← Back to Home

Spring Data JPA

Spring Data JPA simplifies database access by providing repository abstractions that eliminate boilerplate code. It builds on top of JPA (Java Persistence API) and offers powerful features like query methods, pagination, and auditing with minimal configuration.

Key Features

Repository Abstraction

Extend JpaRepository to get CRUD operations, pagination, and sorting without writing implementation code.

Query Methods

Define queries by method names following Spring Data conventions, automatically generating SQL queries.

Custom Queries

Use @Query annotation to write custom JPQL or native SQL queries when needed.

Pagination & Sorting

Built-in support for pagination and sorting with Pageable and Sort interfaces.

Use Cases

CRUD Operations: Simplifying create, read, update, and delete operations
Complex Queries: Building dynamic queries based on method names
Data Access Layer: Creating a clean separation between business logic and data access
Multi-database Support: Working with various relational databases (MySQL, PostgreSQL, H2, etc.)
Auditing: Automatically tracking entity creation and modification dates

Example Usage

Define a repository interface:

public interface UserRepository extends JpaRepository<User, Long> {
    
    List<User> findByEmail(String email);
    
    List<User> findByAgeGreaterThan(int age);
    
    @Query("SELECT u FROM User u WHERE u.active = true")
    List<User> findActiveUsers();
    
    Page<User> findByLastName(String lastName, Pageable pageable);
}

Dependencies

Add the following dependency:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

Configuration

Configure database connection in application.properties:

spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=root
spring.datasource.password=password
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true