使用 Postgres jsonb 类型时，带有 r2dbc 的 Kotlin Micronaut 数据失败

Question

I am trying to set up Micronaut Data r2dbc with Postgres but it fails with

    io.r2dbc.postgresql.ExceptionFactory$PostgresqlBadGrammarException: [42804] column blob is of type jsonb but expression is of type character varying

micronautVersion=3.5.1 kotlinVersion=1.6.10 javaVersion=17

build.gradle.kts

    val coroutinesVersion = "1.6.0"
    dependencies {
        kapt("io.micronaut.data:micronaut-data-processor")
        // kapt("io.micronaut:micronaut-http-validation")
        // implementation("io.micronaut:micronaut-http-client")
        implementation("io.micronaut:micronaut-jackson-databind")
        implementation("io.micronaut.data:micronaut-data-r2dbc")
        implementation("io.micronaut.kotlin:micronaut-kotlin-runtime")
        implementation("jakarta.annotation:jakarta.annotation-api")
        implementation("org.jetbrains.kotlin:kotlin-reflect:${kotlinVersion}")
        implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8:${kotlinVersion}")
        implementation("org.jetbrains.kotlinx:kotlinx-coroutines-reactive:${coroutinesVersion}")
        implementation("org.jetbrains.kotlinx:kotlinx-coroutines-jdk8:${coroutinesVersion}")
        runtimeOnly("ch.qos.logback:logback-classic")
        runtimeOnly("org.postgresql:r2dbc-postgresql")
        implementation("io.micronaut:micronaut-validation")
        implementation("io.micronaut:micronaut-runtime")
        implementation("io.micronaut:micronaut-jackson-databind")
        runtimeOnly("com.fasterxml.jackson.module:jackson-module-kotlin")
    }

Postgres schema

    CREATE TABLE entity (
        entity_id          TEXT PRIMARY KEY,
        entity_type        TEXT NOT NULL,
        blob               JSONB NOT NULL,
        CREATED_DATE       TIMESTAMP(3) DEFAULT now() NOT NULL
    );

Corresponding Kotlin data class

    @MappedEntity
    data class Entity(
      @field:Id val entityId: String,
      val entityType: String,
      @TypeDef(type = DataType.JSON) val blob: Any,
      val createdDate: Instant
    )

The test that fails

    @Test
    fun testInsert() = runBlocking {
        val now = Instant.now()
        val entity = Entity("entity-uuid-1", "test-entity-type", "{}", now)
        Assertions.assertEquals(entity, entityRepository.save(entity))
    }

The complete project is here

It looks like either it's missing a required dependency to convert string to json or need a custom converter for this. Can someone please help.

Answer 1

EDIT: It looks like I was mistaken and the actual problem is with the mapping:

Instead of:

@TypeDef(type = DataType.JSON)

It should be:

@field:TypeDef(type = DataType.JSON)

It looks like R2DBC Postgres driver doesn't allow a String to be used for JSONB, which is strange because JDBC is fine. You might want to try creating AttributeConverter to convert it into byte[] .

Answer 2

I got this working by using

    implementation("io.r2dbc:r2dbc-postgresql:0.8.12.RELEASE")

instead of

    implementation("org.postgresql:r2dbc-postgresql")

The data class was updated to use io.r2dbc.postgresql.codec.Json instead of Any

    @MappedEntity
    data class Entity(
      @field:Id val entityId: String,
      val entityType: String,
      @TypeDef(type = DataType.JSON) val blob: Json,
      val createdDate: Instant
    )