Spring supports

Spring Boot AutoConfigure

Kotlin JDSL supports Spring Boot AutoConfigure. If your project has Spring Boot and one of the following dependencies, AutoConfiguration automatically creates the JpqlRenderContext bean.

• com.linecorp.kotlin-jdsl:spring-data-jpa-support (for Spring Boot 2 or 3)

• com.linecorp.kotlin-jdsl:spring-data-jpa-boot4-support (for Spring Boot 4)

• com.linecorp.kotlin-jdsl:spring-batch-support (for Spring Batch 5)

• com.linecorp.kotlin-jdsl:spring-batch6-support (for Spring Batch 6)

If you declare your JpqlSerializer or JpqlIntrospector as a bean, it will be included with the JpqlRenderContext bean.

EntityManager bean registration for Spring Boot 4

In Spring Boot 4 (Spring Data JPA 4), EntityManagerBeanDefinitionRegistrarPostProcessor has been deprecated, so the EntityManager bean is no longer auto-registered. According to the Spring Data 2025.1 Release Notes, when a shared EntityManager is required, using SharedEntityManagerCreator directly in your configuration is the recommended approach. Since KotlinJdslJpqlExecutor requires an EntityManager, Spring Boot 4 users must register the EntityManager bean manually as follows:

import jakarta.persistence.EntityManager
import jakarta.persistence.EntityManagerFactory
import org.springframework.context.annotation.Bean
import org.springframework.orm.jpa.SharedEntityManagerCreator

@SpringBootApplication
class Application {
    @Bean
    fun entityManager(entityManagerFactory: EntityManagerFactory): EntityManager =
        SharedEntityManagerCreator.createSharedEntityManager(entityManagerFactory)
}

Kotlin JDSL respects Spring Boot 4's design decision and does not forcibly add the EntityManager bean in AutoConfiguration.

Spring Data Repository

If your JpaRepository extends KotlinJdslJpqlExecutor, you can use the extension provided by Kotlin JDSL.

interface BookRepository : JpaRepository<Book, Isbn>, KotlinJdslJpqlExecutor

val result: List<Isbn?> = bookRepository.findAll {
    select(
        path(Book::isbn),
    ).from(
        entity(Book::class),
    )
}

val result: Page<Isbn?> = bookRepository.findPage(pageable) {
    select(
        path(Book::isbn),
    ).from(
        entity(Book::class),
    )
}

val result: Slice<Isbn?> = bookRepository.findSlice(pageable) {
    select(
        path(Book::isbn),
    ).from(
        entity(Book::class),
    )
}

val result: Stream<Isbn?> = bookRepository.findStream {
    select(
        path(Book::isbn),
    ).from(
        entity(Book::class),
    )
}

If you want to use KotlinJdslJpqlExecutor in @DataJpaTest, you need to import KotlinJdslAutoConfiguration in the test. Since @DataJpaTest is a slice test, it only creates minimal beans. And the minimal bean does not include KotlinJdslAutoConfiguration. So if you want to use the features of Kotlin JDSL in @DataJpaTest, you need to import KotlinJdslAutoConfiguration directly in your test.

Spring Batch

Spring Batch provides JpaPagingItemReader and JpaCursorItemReader for querying data with JPQL. Kotlin JDSL provides KotlinJdslQueryProvider so that a JPQL query created in DSL can be executed in it.

@Auwoired
lateinit var queryProviderFactory: KotlinJdslQueryProviderFactory

val queryProvider = queryProviderFactory.create {
    select(
        path(Book::isbn)
    ).from(
        entity(Book::class),
    )
}

JpaCursorItemReaderBuilder<Isbn>()
    .entityManagerFactory(entityManagerFactory)
    .queryProvider(queryProvider)
    .saveState(false)
    .build()