Json format with Play 2.4 / Scala

Question

我知道这个问题已经被问了上千次了，但是我不明白为什么这个代码不能正常工作。

case class Partner
(_id: Option[BSONObjectID], name: String, beacon: Option[Beacon])
class PartnerFormatter @Inject() (val beaconDao: BeaconDao){
  implicit val partnerReads: Reads[Partner] = (
      (__  "_id").readNullable[String]and
      (__  "name").read[String] and
      (__  "beacon").read[String]
    )((_id, name, beaconID) => Partner(_id.map(BSONObjectID(_)), name, Await.result(beaconDao.findById(beaconID), 1 second))))
  implicit val partnerWrites: Writes[Partner] = (
        (JsPath  "_id").writeNullable[String].contramap((id: Option[BSONObjectID]) => Some(id.get.stringify)) and
        (JsPath  "name").write[String] and
        (JsPath  "beacon").writeNullable[String].contramap((beacon: Option[Beacon]) => Some(beacon.get._id.get.stringify))
      )(unlift(Partner.unapply))
}

我面对着

No Json deserializer found for type models.Partner. Try to implement an implicit Reads or Format for this type

或

No Json deserializer found for type models.Partner. Try to implement an implicit Writes or Format for this type

Answer 1

您需要在Partner 对象中定义阅读器和写入器。

这是一个例子，https://github.com/luongbalinh/play-mongo/blob/master/app/models/User.scala