scala play Read json有条件地填充案例类

我有一个json，我正在使用play json api读取

 {
  "runId" : "123",
  "name" : "ABC",
  "location" : "DEF"
}

implicit val jsonRead: Reads[Contact] = (
        (JsPath \ "runId").readWithDefault(generateRunId) and
          (JsPath \ "name").read[String] and
          (JsPath \ "location").read[String]
    )(Contact.apply _)

case class Contact(runId : String, name : String, location : String, rerun : Boolean)

---

我想在联系人中添加最后一个属性重新运行，以便在json文件中确实存在“runId”时，将其设置为true。这怎么可能呢？

您可以使用

readNullable

和

map

：

implicit val jsonRead: Reads[Contact] = (
  (JsPath \ "runId").readWithDefault(generateRunId) and
    (JsPath \ "name").read[String] and
    (JsPath \ "location").read[String] and
    (JsPath \ "runId").readNullable[String].map(_.nonEmpty)
)(Contact.apply _)