创建 Reads for Play 2.1 时出现类型不匹配错误

Question

我已经玩了好几个小时了。我一直在尝试不同的方法来创建阅读，但我完全被难住了。

我在 Play 2.1.0 和 Scala 2.10.1

错误：

type mismatch; found : models.Registration.type required: play.api.libs.json.Reads[?]

代码：

package models

import play.api.libs.json._
import play.api.libs.functional.syntax._

case class Registration(
        user: (String,String,String,String,String,String)
)

object RegistrationHelper {
    implicit val regReads: Reads[Registration] = (
      (__ \ "user").read(
        (__ \ "id").read[String] and
        (__ \ "username").read[String] and
        (__ \ "first_name").read[String] and
        (__ \ "last_name").read[String] and
        (__ \ "email_address").read[String] and
        (__ \ "user_avatar").read[String]
        tupled
      )
    )(Registration) //!!ERROR ON THIS LINE
}

JSON：

{
  user: {
    id: "35fc8ba5-56c3-4ebe-9a21-489a1a207d2e",
    username: "flastname",
    first_name: "Firstname",
    last_name: "Lastname",
    email_address: "foo@bar.com",
    user_avatar: "http://blog.ideeinc.com/wp-content/uploads/2010/04/tineye-robot.jpg"
  }
}

Answer 1

这应该可行：

implicit val regReads: Reads[Registration] = (__ \ "user").read(
    (__ \ "id").read[String] and
      (__ \ "username").read[String] and
      (__ \ "first_name").read[String] and
      (__ \ "last_name").read[String] and
      (__ \ "email_address").read[String] and
      (__ \ "user_avatar").read[String]
      tupled
  ) map Registration.apply _

有关更多信息，请参阅this 问题。