Question

我正在尝试将使用Play的WSClient所获得的json正文响应反序列化为对象列表，并且我认为离成功还不太远，但是可能还有最后一个难题想念我。

这些是案例类（及其伴随对象），传入的json必须反序列化到。

EmployerStoreDTO：

import play.api.libs.json._

case class EmployerStoreDTO (id: String, storeName: String)

object EmployerStoreDTO {
  implicit val reads: Reads[EmployerStoreDTO] = Json.reads[EmployerStoreDTO]

  implicit val employerStoreDTOlistReads: Reads[List[EmployerStoreDTO]] = Reads.list[EmployerStoreDTO]
}

CompanyEmployerDTO：

import java.time.DayOfWeek

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

case class CompanyEmployerDTO(id: String,
                              companyName: String,
                              companyUrl: Option[String],
                              description: Option[String],
                              startDayOfWeek: DayOfWeek,
                              logoUrl: Option[String],
                              stores: List[EmployerStoreDTO] = List(),
                              supportHelpText: Option[String],
                              themeId: Option[String]) {
}

object CompanyEmployerDTO {

  import model.EmployerStoreDTO._

  implicit val startDayOfWeekReads: Reads[DayOfWeek] = (JsPath \ "weekStartDay").read[Int].map(DayOfWeek.of)

  implicit val reads: Reads[CompanyEmployerDTO] = (
    (JsPath \ "id").read[String] and
      (JsPath \ "companyName").read[String] and
      (JsPath \ "companyUrl").readNullable[String] and
      (JsPath \ "description").readNullable[String] and startDayOfWeekReads and
      (JsPath \ "logoUrl").readNullable[String] and employerStoreDTOlistReads and
      (JsPath \ "supportHelpText").readNullable[String] and
      (JsPath \ "themeId").readNullable[String]
    ) (CompanyEmployerDTO.apply _)

  implicit val companyEmployerDTOListReads: Reads[List[CompanyEmployerDTO]] = Reads.list[CompanyEmployerDTO]
}

CompanyEmployerCollectionDTO：

import play.api.libs.json.Reads._
import play.api.libs.json._

case class CompanyEmployerCollectionDTO (companies: List[CompanyEmployerDTO])

object CompanyEmployerCollectionDTO {

  implicit val reads: Reads[CompanyEmployerCollectionDTO] =
    (JsPath \ "companies").read[List[CompanyEmployerDTO]].map(CompanyEmployerCollectionDTO.apply)

}

我看到我的WsClient收到了有效载荷：

但是当我尝试反序列化响应时，如下所示：response.json.as[CompanyEmployerCollectionDTO]

我收到此错误：

Caused by: play.api.libs.json.JsResultException: JsResultException(errors:List((/companies(0),List(JsonValidationError(List(error.expected.jsarray),WrappedArray())))))
    at play.api.libs.json.JsReadable.$anonfun$as$2(JsReadable.scala:25)
    at play.api.libs.json.JsError.fold(JsResult.scala:64)
    at play.api.libs.json.JsReadable.as(JsReadable.scala:24)
    at play.api.libs.json.JsReadable.as$(JsReadable.scala:23)
    at play.api.libs.json.JsObject.as(JsValue.scala:124)
    at services.com.mycompany.ApiEmployeeClient.$anonfun$callGetEmployers$2(ApiEmployeeClient.scala:33)
    at scala.util.Success.$anonfun$map$1(Try.scala:255)
    at scala.util.Success.map(Try.scala:213)
    at scala.concurrent.Future.$anonfun$map$1(Future.scala:292)
    at scala.concurrent.impl.Promise.liftedTree1$1(Promise.scala:33)

Answer 1

问题是裸露的and employerStoreDTOlistReads。因为您尚未指定路径（对于其他CompanyEmployerDTO成员），所以解码器将尝试将当前JSON值本身（代表CompanyEmployerDTO的对象）解码为{{1 }}。

用EmployerStoreDTO替换这两个词应该可以修复您的代码，但是值得的是，您也可以通过废弃and (JsPath \ "stores").read[List[EmployerStoreDTO]]实例（将自动提供），从而简化实现，删除导入等：

List

这将与您的代码完全相同，但是更加简洁和易于管理。

Play2 Scala：将Json反序列化为对象列表

1 个答案: