PlayFramework：如何转换 JSON 数组的每个元素

Question

鉴于以下 JSON...

{
  "values" : [
     "one",
     "two",
     "three"
  ]
}

...我如何在 Scala/Play 中像这样转换它？

{
  "values" : [
     { "elem": "one" },
     { "elem": "two" },
     { "elem": "three" }
  ]
}

Answer 1

您可以使用 Play 的 JSON API：

import play.api.libs.json._

val json = Json parse """
    {
      "values" : [
         "one",
         "two",
         "three"
      ]
    }
  """

val newArray = json \ "values" match {
  case JsArray(values) => values.map { v => JsObject(Seq("elem" -> v)) }
}

// or Json.stringify if you don't need readability
val str = Json.prettyPrint(JsObject(Seq("values" -> JsArray(newArray))))

输出：

{
  "values" : [ {
    "elem" : "one"
  }, {
    "elem" : "two"
  }, {
    "elem" : "three"
  } ]
}

Answer 2

使用 Play's JSON Transformers 很容易：

val json = Json.parse(
  """{
    |  "somethingOther": 5,
    |  "values" : [
    |     "one",
    |     "two",
    |     "three"
    |  ]
    |}
  """.stripMargin
)

// transform the array of strings to an array of objects
val valuesTransformer = __.read[JsArray].map {
  case JsArray(values) =>
    JsArray(values.map { e => Json.obj("elem" -> e) })
}

// update the "values" field in the original json
val jsonTransformer = (__ \ 'values).json.update(valuesTransformer)

// carry out the transformation
val transformedJson = json.transform(jsonTransformer)

PlayFramework：如何转换 JSON 数组的每个元素

PlayFramework: how to transform each element of a JSON array

scala

playframework