scala按顺序解析json对象

Question

我有以下json输入，我试图按顺序解析name字段。

scala> result
res6: play.api.libs.json.JsValue = {"L0": 
{"name":"FASHION","id":"50000"},"L1":{"name":"ACCESSORIES AND TRAVEL","id":"51000"},"L2":{"name":"FASHION ACCESSORIES","id":"51001"},"L3":{"name":"MENS FASHION ACCESSORIES","id":"51100"},"L4":{"name":"MENS HATS","id":"51204"}}

scala> result \\ "name"
res5: Seq[play.api.libs.json.JsValue] = List("ACCESSORIES AND TRAVEL", "MENS HATS", "MENS FASHION ACCESSORIES", "FASHION ACCESSORIES", "FASHION")

我试着把这些名字按顺序排列

List("FASHION", "ACCESSORIES AND TRAVEL", "FASHION ACCESSORIES", "MENS FASHION ACCESSORIES", "MENS HATS")

是否有办法通过play Json库实现这一目标？

Answer 1

对于Play JSON，我总是使用case classes。所以你的例子应该是：

导入play.api.libs.json._

val json = """{"L0": 
{"name":"FASHION","id":"50000"},"L1":{"name":"ACCESSORIES AND TRAVEL","id":"51000"},"L2":{"name":"FASHION ACCESSORIES","id":"51001"},"L3":{"name":"MENS FASHION ACCESSORIES","id":"51100"},"L4":{"name":"MENS HATS","id":"51204"}}
"""

case class Element(id: String, name: String)
object Element {
  implicit val jsonFormat: Format[Element] = Json.format[Element]
}

Json.parse(json).validate[Map[String, Element]] match {
  case JsSuccess(elems, _) => println(elems.toList.sortBy(_._1).map(e => e._2.name))
  case other => println(s"Handle exception $other")
}

这给了你，是你可以排序结果的关键-信息丢失在你的解决方案。