✅ Configuring and Creating Spring Data Repositories

This section demonstrates how to eliminate DAO boilerplate using Spring Data JPA’s CrudRepository. You’ll see how to configure persistence, define real repositories, and use them in services — all with your Movie, Actor, Studio domain model.

🔧 1. Spring JPA Configuration (Jakarta EE 8 Compatible)

@Configuration
@EnableJpaRepositories(basePackages = "com.nicordesigns.repository")
public class JpaConfig {

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory(DataSource dataSource) {
        LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
        emf.setDataSource(dataSource);
        emf.setPackagesToScan("com.nicordesigns.entities");
        emf.setJpaVendorAdapter(new HibernateJpaVendorAdapter());

        Properties props = new Properties();
        props.put("hibernate.dialect", "org.hibernate.dialect.MariaDBDialect");
        props.put("hibernate.hbm2ddl.auto", "update");
        props.put("hibernate.show_sql", "true");
        emf.setJpaProperties(props);

        return emf;
    }

    @Bean
    public PlatformTransactionManager transactionManager(EntityManagerFactory emf) {
        return new JpaTransactionManager(emf);
    }
}

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📁 2. Define Real CrudRepository Interfaces

🎬 MovieRepository2

@Repository
public interface MovieRepository2 extends CrudRepository<Movie, Long> {

    List<Movie> findByTitleContainingIgnoreCase(String titleFragment);

    @Query("SELECT m FROM Movie m WHERE m.studio.studioName = ?1")
    List<Movie> findByStudioName(String studioName);

    @EntityGraph(attributePaths = {"actors", "studio"})
    @Query("SELECT m FROM Movie m")
    List<Movie> findAllWithActorsAndStudio();
}

🏢 StudioRepository

@Repository
public interface StudioRepository extends CrudRepository<Studio, Long> {

    List<Studio> findByStudioNameContainingIgnoreCase(String studioName);

    List<Studio> findByYearFounded(Year year);
}

💡 CrudRepository<T, ID> provides basic persistence operations:
save(), findById(), findAll(), deleteById(), count(), etc.

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🧪 3. Using the Repositories in Service Classes

🎬 MovieService2

@Service
public class MovieService2 {

    @Autowired
    private MovieRepository2 movieRepository2;

    @Transactional
    public Movie saveMovie(Movie movie) {
        return movieRepository2.save(movie);
    }

    @Transactional(readOnly = true)
    public List<Movie> getAllMoviesWithDetails() {
        return movieRepository2.findAllWithActorsAndStudio();
    }

    @Transactional(readOnly = true)
    public List<Movie> searchByTitle(String keyword) {
        return movieRepository2.findByTitleContainingIgnoreCase(keyword);
    }
}

🏢 StudioService

@Service
public class StudioService {

    @Autowired
    private StudioRepository studioRepository;

    @Transactional
    public Studio createStudio(Studio studio) {
        return studioRepository.save(studio);
    }

    @Transactional(readOnly = true)
    public List<Studio> searchStudiosByName(String keyword) {
        return studioRepository.findByStudioNameContainingIgnoreCase(keyword);
    }

    @Transactional
    public void deleteStudioById(Long id) {
        if (!studioRepository.existsById(id)) {
            throw new IllegalArgumentException("Studio ID not found: " + id);
        }
        studioRepository.deleteById(id);
    }
}

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✅ Summary

With CrudRepository, you can:

• Rapidly prototype JPA-based apps without writing DAO implementations
• Use derived queries and custom JPQL to fetch meaningful data
• Load entity relationships using @EntityGraph to avoid N+1 issues
• Keep your service layer focused on business logic and transactions

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