SpringBoot+Kotlin+Postgres and JSONB: “org.hibernate.MappingException: No Dialect mapping for JDBC type”

Question

I have been consulting a number of approaches/posts/stackoverflow questions in order to deal with the following error (full stack trace) when running a Kotlin/SpringBoot app

Answer 1

I propose my solution in a pull-request

The idea is to change Entity to:

import com.example.demo.pojo.SamplePojo
import com.vladmihalcea.hibernate.type.json.JsonBinaryType
import com.vladmihalcea.hibernate.type.json.JsonStringType
import org.hibernate.annotations.Type
import org.hibernate.annotations.TypeDef
import org.hibernate.annotations.TypeDefs
import javax.persistence.*

@Entity
@Table(name = "tests")
@TypeDefs(
        TypeDef(name = "json", typeClass = JsonStringType::class),
        TypeDef(name = "jsonb", typeClass = JsonBinaryType::class)
)
data class SampleEntity (
    @Id @GeneratedValue
    val id: Long?,
    val name: String?,

    @Type(type = "jsonb")
    @Column(columnDefinition = "jsonb")
    var data: Map?
) {

    /**
     * Dependently on use-case this can be done differently:
     * https://stackoverflow.com/questions/37873995/how-to-create-empty-constructor-for-data-class-in-kotlin-android
     */
    constructor(): this(null, null, null)
}

1. Each entity should either have a default constructor or have defaults for all its parameters
2. Instead of saving POJO, save as Map type

Since we have a full-control what will be in POJO in business logic the only missing piece will be to convert POJO to Map and Map to POJO

SamplePojo implementation

data class SamplePojo(
        val payload: String,
        val flag: Boolean
)  {
    constructor(map: Map) : this(map["payload"] as String, map["flag"] as Boolean)

    fun toMap() : Map {
        return mapOf("payload" to payload, "flag" to flag)
    }
}

This is rather a workaround but it allows us to work with any depth-level structures.

P.S. I noticed that you use Serializer and redefined equals, toString, hashCode. You don't need this if using data class.

UPDATE:

If you need a more flexible structure than Map, you can use JsonNode. Code example

Entity:

import com.fasterxml.jackson.databind.JsonNode
import com.vladmihalcea.hibernate.type.json.JsonBinaryType
import com.vladmihalcea.hibernate.type.json.JsonStringType
import org.hibernate.annotations.Type
import org.hibernate.annotations.TypeDef
import org.hibernate.annotations.TypeDefs
import javax.persistence.*

@Entity
@Table(name = "tests")
@TypeDefs(
        TypeDef(name = "json", typeClass = JsonStringType::class),
        TypeDef(name = "jsonb", typeClass = JsonBinaryType::class)
)
data class SampleJsonNodeEntity (
        @Id @GeneratedValue
        val id: Long?,
        val name: String?,

        @Type(type = "jsonb")
        @Column(columnDefinition = "jsonb")
        var data: JsonNode?
) {

    /**
     * Dependently on use-case this can be done differently:
     * https://stackoverflow.com/questions/37873995/how-to-create-empty-constructor-for-data-class-in-kotlin-android
     */
    constructor(): this(null, null, null)
}

Change Entity in Repository:

import com.example.demo.entity.SampleJsonNodeEntity
import org.springframework.data.jpa.repository.JpaRepository

interface SampleJsonNodeRepository: JpaRepository {
}

Tests for both approaches:

import com.example.demo.DbTestInitializer
import com.example.demo.entity.SampleJsonNodeEntity
import com.example.demo.entity.SampleMapEntity
import com.example.demo.pojo.SamplePojo
import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
import junit.framework.Assert.assertEquals
import junit.framework.Assert.assertNotNull
import org.junit.Before
import org.junit.Test
import org.junit.runner.RunWith
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase
import org.springframework.boot.test.context.SpringBootTest
import org.springframework.test.context.ContextConfiguration
import org.springframework.test.context.junit4.SpringRunner


@RunWith(SpringRunner::class)
@SpringBootTest
@ContextConfiguration(initializers = [DbTestInitializer::class])
@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
class SampleRepositoryTest {

    @Autowired
    lateinit var sampleMapRepository: SampleMapRepository

    @Autowired
    lateinit var sampleJsonNodeRepository: SampleJsonNodeRepository

    lateinit var dto: SamplePojo
    lateinit var mapEntity: SampleMapEntity
    lateinit var jsonNodeEntity: SampleJsonNodeEntity

    @Before
    fun setUp() {
        dto = SamplePojo("Test", true)
        mapEntity = SampleMapEntity(null,
                "POJO1",
                dto.toMap()
        )

        jsonNodeEntity = SampleJsonNodeEntity(null,
            "POJO2",
                jacksonObjectMapper().valueToTree(dto)
        )
    }

    @Test
    fun createMapPojo() {
        val id = sampleMapRepository.save(mapEntity).id!!
        assertNotNull(sampleMapRepository.getOne(id))
        assertEquals(sampleMapRepository.getOne(id).data?.let { SamplePojo(it) }, dto)
    }

    @Test
    fun createJsonNodePojo() {
        val id = sampleJsonNodeRepository.save(jsonNodeEntity).id!!
        assertNotNull(sampleJsonNodeRepository.getOne(id))
        assertEquals(jacksonObjectMapper().treeToValue(sampleJsonNodeRepository.getOne(id).data, SamplePojo::class.java), dto)
    }

}