Spring Data JPA Repository Creator

Name: spring-data-jpa-repo-creator
Rating: 76
Author: sivaprasadreddy

Instructions

The following are key principles to follow while creating Spring Data JPA Repositories:

•Make sure to create the recommended package structure for Spring Boot projects
•Create repositories only for aggregate roots
•Use @Query with JPQL for custom queries
•Prefer meaningful method names over long Spring Data JPA finder methods
•Use constructor expressions or Projections for read operations
•Use default methods for convenience operations

Example: EventRepository

File: events/domain/EventRepository.java

java

interface EventRepository extends JpaRepository<EventEntity, EventId> {

    @Query("""
            SELECT e FROM EventEntity e
            WHERE e.startDatetime > :now
            ORDER BY e.startDatetime ASC
            """)
    List<EventEntity> findUpcomingEvents(@Param("now") Instant now);

    @Query("""
            SELECT e FROM EventEntity e
            WHERE e.code = :code
            """)
    Optional<EventEntity> findByCode(@Param("code") EventCode code);

    // Convenience methods using default interface methods
    default EventEntity getByCode(EventCode eventCode) {
        return this.findByCode(eventCode)
                .orElseThrow(() -> new ResourceNotFoundException("Event not found with code: " + eventCode));
    }
}

Enable JPA Auditing

Enable JPA Auditing support to automatically populate createdAt and updatedAt fields.

•Add @CreatedDate and @LastModifiedDate annotations to your BaseEntity class.
•Add @EntityListeners(AuditingEntityListener.class) to your BaseEntity class.
•Create a Spring @Configuration class and add @EnableJpaAuditing annotation.

java

package dev.sivalabs.meetup4j.shared;

import jakarta.persistence.Column;
import jakarta.persistence.EntityListeners;
import jakarta.persistence.MappedSuperclass;
import org.springframework.data.annotation.CreatedDate;
import org.springframework.data.annotation.LastModifiedDate;
import org.springframework.data.jpa.domain.support.AuditingEntityListener;

import java.time.Instant;

@MappedSuperclass
@EntityListeners(AuditingEntityListener.class)
public abstract class BaseEntity {

    @Column(name = "created_at", nullable = false, updatable = false)
    @CreatedDate
    protected Instant createdAt;

    @Column(name = "updated_at", nullable = false)
    @LastModifiedDate
    protected Instant updatedAt;

    // Getters and setters
}

Enable JPA Auditing in your application configuration:

java

@Configuration
@EnableJpaAuditing
public class JpaConfig {
}