播放框架:读取包含空值的Json [英] Play framework: read Json containing null values

问题描述

我正在尝试在Play Scala程序中读取Json数据. Json的某些字段中可能包含空值，因此这就是我定义Reads对象的方式:

I'm trying to read Json data in my Play Scala program. The Json may contain nulls in some fields, so this is how I defined the Reads object:

  implicit val readObj: Reads[ApplyRequest] = (
      (JsPath \ "a").read[String] and
      (JsPath \ "b").read[Option[String]] and
      (JsPath \ "c").read[Option[String]] and
      (JsPath \ "d").read[Option[Int]]
    )  (ApplyRequest.apply _) 

和ApplyRequest案例类:

And the ApplyRequest case class:

case class ApplyRequest ( a: String,
                          b: Option[String],
                          c: Option[String],
                          d: Option[Int],
                          )

无法编译，我得到No Json deserializer found for type Option[String]. Try to implement an implicit Reads or Format for this type.

如何声明Reads对象以接受可能的null?

How to declare the Reads object to accept possible nulls?

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