没有为类型为play.api.libs.json.JsObject的JsObject找到Json序列化程序

Question

我有以下代码在引用时在控制台应用程序中工作 "org.reactivemongo" %% "play2-reactivemongo" % "0.10.5.0.akka23"

当我更新对我的引用时"org.reactivemongo" % "play2-reactivemongo_2.11" % "0.11.0.play23-M3":

没有为类型为play.api.libs.json.JsObject的JsObject找到Json序列化程序.尝试为此类型实现隐式OWrites或OFormat.

import org.joda.time.DateTime
import reactivemongo.bson.BSONObjectID
import play.modules.reactivemongo.json.BSONFormats._

case class GoogleToken
(
  id: Option[BSONObjectID],
  name: String,
  emailAddress: String,
  refreshToken: String,
  expires: DateTime
  )

object GoogleToken {

  import play.api.libs.json.Json

  // Generates Writes and Reads
  implicit val googleTokenFormat = Json.format[GoogleToken]
}

然后

val collection = db.collectionJSONCollection

val query = Json.obj()
val cursor = collection.find(query).
  cursor[GoogleToken](ReadPreference.nearest).
  collect[List]()

我究竟做错了什么？

Answer 1

ReactiveMongo 0.11的最终版本已发布("org.reactivemongo" %% "play2-reactivemongo" % "0.11.0.play23").

如更新文档所示,对于默认的BSON/JSON转换,建议使用:import play.modules.reactivemongo.json._, ImplicitBSONHandlers._.

Answer 2

在我的情况下,我insert用JsValue反而不是a来喂ReactiveMongo()JsObject.为了解决这个问题,后面加入import play.modules.reactivemongo.json._,我也不得不改变我隐Writes在OWrites:

从

implicit val myWrites: Writes[A] = new Writes[A] {
  def writes(a: A) = Json.obj(...)

至

implicit val myWrites: OWrites[A] = new OWrites[A] {  <-- NOTE THE 'O' before 'Writes'
  def writes(a: A) = Json.obj(...)

Answer 3

我在添加之后计算出:import play.modules.reactivemongo.json._ import play.modules.reactivemongo.json.collection._