我有多个共享相同属性的模型类。因此，我创建了一个特征，例如:
trait Player extends Temp {
val gameId: BSONObjectID
val personalDetails: abc.PersonalDetails // <- comes from shared library
}
case class FootballPlayer(var _id: Option[BSONObjectID] = None,
gameId: BSONObjectID,
personalDetails: abc.PersonalDetails,
var created: Option[DateTime] = None,
var updated: Option[DateTime] = None
) extends Player
case class VideogamePlayer(var _id: Option[BSONObjectID] = None,
gameId: BSONObjectID,
personalDetails: abc.PersonalDetails,
var created: Option[DateTime] = None,
var updated: Option[DateTime] = None
) extends Player
所有这些模型都定义了
play.api.libs.json.Reads和play.api.libs.json.OWrites作为伴随对象。例如:
object FootballPlayer {
import play.api.libs.functional.syntax._
import play.api.libs.json.Reads._
import play.api.libs.json._
import reactivemongo.play.json.BSONFormats.BSONObjectIDFormat
implicit val footballPlayerReads: Reads[FootballPlayer] = (
(__ \ "_id").readNullable[BSONObjectID].map(_.getOrElse(BSONObjectID.generate)).map(Some(_)) and
(__ \ "gameId").read[BSONObjectID] and
(__ \ "personalDetails").read[abc.PersonalDetails] and
(__ \ "created").readNullable[DateTime].map(_.getOrElse(new DateTime())).map(Some(_)) and
(__ \ "updated").readNullable[DateTime].map(_.getOrElse(new DateTime())).map(Some(_))
) (FootballPlayer.apply _)
implicit val sharedPersonalDetailsWrites: Writes[abc.PersonalDetails] = abc.PersonalDetails.sharedPersonalDetailsWrites
implicit val footballPlayerWrites: OWrites[FootballPlayer] = (
(__ \ "_id").writeNullable[BSONObjectID] and
(__ \ "gameId").write[BSONObjectID] and
(__ \ "personalDetails").write[abc.PersonalDetails] and
(__ \ "created").writeNullable[DateTime] and
(__ \ "updated").writeNullable[DateTime]
) (unlift(FootballPlayer.unapply))
}
现在，我想将它们存储在不同的集合中，但是我只想拥有一个DAO，因此我实现了以下内容:
trait PlayerDAO[T <: Player] {
def findById(_id: BSONObjectID)(implicit reads: Reads[T]): Future[Option[T]]
def insert(t: T)(implicit writes: OWrites[T]): Future[T]
}
class MongoPlayerDAO[T <: Player] @Inject()(
playerRepository: PlayerRepository[T]
) extends PlayerDAO[T] {
def findById(_id: BSONObjectID)(implicit reads: Reads[T]): Future[Option[T]] = playerRepository.findById(_id)
def insert(t: T)(implicit writes: OWrites[T]): Future[T] = playerRepository.insert(t).map(_ => t)
}
然后，我有以下存储库:
class PlayerService[T <: Player] @Inject()(playerDAO: PlayerDAO[T])(implicit reads: Reads[T], writes: OWrites[T]) {
def findById(_id: BSONObjectID): Future[Option[T]] = playerDAO.findById(_id)
def save(t: T): Future[T] = playerDAO.save(t)
}
我的模块如下所示:
class PlayerModule extends AbstractModule with ScalaModule {
def configure() {
bind[PlayerDAO[FootballPlayer]].to[MongoPlayerDAO[FootballPlayer]]
bind[PlayerDAO[VideogamePlayer]].to[MongoPlayerDAO[VideogamePlayer]]
// ...
()
}
}
然后在我的Play Controller 中注入(inject)以下内容:
import models.FootballPlayer._
import models.VideogamePlayer._
class PlayerController @Inject()(
val messagesApi: MessagesApi,
footballPlayerService: PlayerService[FootballPlayer],
videogamePlayerService: PlayerService[VideogamePlayer]
) extends Controller with I18nSupport
但是，不幸的是，我得到以下异常:
我怎样才能解决这个问题？
最佳答案
进行dao注入(inject)时，可能无法找到隐式上下文。尝试在定义绑定(bind)的AbstractModule中包含隐式函数。
编辑
检查我对git的解决方案。 Here
我试图模仿您想做的任何事情，并且工作正常。
我不确定您当前的代码是什么问题，因为我无法访问整个代码，但是我认为这与应用程序搜索OWrites和Reads隐式表示Player而不是FootballPlayer或VideoGamePlayer有关
关于scala - Scala Play应用程序未绑定(bind)OWrites和Reads的实现，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/43569720/