PlayFramework:如何转换JSON数组的每个元素

Question

鉴于以下JSON ......

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

...如何在Scala/Play中将其转换为这样？

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

Answer 1

Play的JSON变形金刚很容易:

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)