Kotlin Hibernate

• I find this article is simple & easy to implement, Kotlin & Hibernate

• You can also find Hibernate Entity Document.

• Some update about configuration

plugins {
    id("org.springframework.boot") version "2.6.3"
    id("io.spring.dependency-management") version "1.0.11.RELEASE"
    kotlin("jvm") version "1.6.10"
    kotlin("plugin.spring") version "1.6.10"
    kotlin("plugin.allopen") version "1.6.10"
    kotlin("plugin.jpa") version "1.6.10"
}
allOpen {

annotation("javax.persistence.Entity")

annotation("javax.persistence.MappedSuperclass")

annotation("javax.persistence.Embeddable")

}

• AbstractJpaPersistable in article

import org.springframework.data.domain.Persistable
import org.springframework.data.util.ProxyUtils
import java.io.Serializable
import javax.persistence.GeneratedValue
import javax.persistence.Id
import javax.persistence.MappedSuperclass
import javax.persistence.Transient
/**


Abstract base class for entities. Allows parameterization of id type, chooses auto-generation and implements


[equals] and [hashCode] based on that id.



This class was inspired by [org.springframework.data.jpa.domain.AbstractPersistable], which is part of the Spring Data project.

*/

@MappedSuperclass

abstract class AbstractJpaPersistable<T : Serializable> : Persistable<T> {
companion object {

private val serialVersionUID = -5554308939380869754L

}
@Id

@GeneratedValue

private var id: T? = null
override fun getId(): T? {

return id

}
/**

Must be [Transient] in order to ensure that no JPA provider complains because of a missing setter.

@see org.springframework.data.domain.Persistable.isNew

*/

@Transient

override fun isNew() = null == getId()

override fun toString() = "Entity of type ${this.javaClass.name} with id: $id"
override fun equals(other: Any?): Boolean {

other ?: return false
 if (this === other) return true

 if (javaClass != ProxyUtils.getUserClass(other)) return false

 other as AbstractJpaPersistable&lt;*&gt;

 return if (null == this.getId()) false else this.getId() == other.getId()

}
override fun hashCode(): Int {

return 31

}

}

Conclusion

Hibernate is not suitable for kotlin ORM, we are currently using native SQL, then will test kotlin oriented ORM.