Quarkus Panache MongoDB: Serialize ObjectId as String - mongodb

Question

I'm following the tutorials https://quarkus.io/guides/rest-data-panache and https://quarkus.io/guides/mongodb-panache to implement a simple MongoDB entity and resource with Quarkus Panache MongoDB.
Here's what I have so far:
#MongoEntity(collection = "guests")
class GuestEntity(
var id: ObjectId? = null,
var name: String? = null
)
#ApplicationScoped
class GuestRepository: PanacheMongoRepository<GuestEntity>
interface GuestResource: PanacheMongoRepositoryResource<GuestRepository, GuestEntity, ObjectId>
When running this, I can create a document by calling
POST localhost:8080/guest
Content-Type: application/json
{
"name": "Foo"
}
The response contains the created entity
{
"id": {
"timestamp": 1618306409,
"date": 1618306409000
},
"name": "Foo"
}
Notice, how the id field is an object whereas I would like it to be a string.

Answer 1

It turns out that the application was using quarkus-resteasy instead of quarkus-resteasy-jackson.
Once the proper dependency was in place, everything worked as expected

Answer 2

To serialize the id field as a String, apply the following annotation to the id field:
import com.fasterxml.jackson.databind.annotation.JsonSerialize
import io.quarkus.mongodb.panache.jackson.ObjectIdSerializer
#MongoEntity(collection = "guests")
class GuestEntity(
// important: apply the annotation to the field
#field:JsonSerialize(using = ObjectIdSerializer::class)
var id: ObjectId? = null,
var name: String
)
Now the response is
{
"id": "607567590ced4472ce95be23",
"name": "Foo"
}