CODEWITHSUNDEEP
jsonscalaplayframework
Luke
Luke

Reputation: 35

parsing json in scala which contains map

I'm trying to parse json string with scala and playframework, I've read doc but still I'm stuck. I got:

val jsonStr = """{
           |    "metric": "java.lang.Memory.HeapMemoryUsage.committed",
           |    "tags": {
           |      "instanceId": "ubuntu",
           |      "runId": "B_name_of_the_app-c4m8_0_2016-01-01_23-31-34"
           |    },
           |    "aggregateTags": [],
           |    "dps": {
           |      "1455711498": 8.71890944E8,
           |      "1455711558": 9.10688256E8,
           |      "1455711618": 9.24319744E8,
           |      "1455711678": 8.47773696E8,
           |      "1455711738": 9.35329792E8,
           |      "1455711798": 9.53679872E8,
           |      "1455714981": 1.983905792E9,
           |      "1455715041": 2.054684672E9,
           |      "1455715101": 2.05520896E9
           |    }
           |  }""".stripMargin

according to playframework doc I created classes to parse this thing:

// start of the scala file

import play.api.libs.json.{JsPath, Json, Reads}
import play.api.libs.functional.syntax._

case class Metric(metricName: String, tags: Tags, aggregateTags: Option[Seq[String]], dps: Seq[Map[String,Double]])

object Metric{

implicit val metricReads: Reads[Metric] = (
(JsPath \ "metric").read[String] and
  (JsPath \ "tags").read[Tags] and
  (JsPath \ "aggreagateTags").readNullable[Seq[String]] and
  (JsPath \ "dps").read[Seq[Map[String,Double]]]  //this one is tricky
)(Metric.apply _)
}

case class Tags(instanceId:String, runId: String)

object Tags{
implicit val tagsReads: Reads[Tags] = (
(JsPath \ "instanceId").read[String] and (JsPath \ "runId").read[String]
)(Tags.apply _)
}

Json.parse(jsonStr).validate[Metric]

// end of the scala file Unfortunately validation results with:

res0: play.api.libs.json.JsResult[Metric] = JsError(List((//dps,List(ValidationError(List(error.expected.jsarray),WrappedArray())))))

I'm not sure how to solve this problem, also tried parse dps' as a separate class but also didn't work..Any tips?

Upvotes: 0

Views: 258

Answers (1)

Sean Vieira
Sean Vieira

Reputation: 160083

You have (JsPath \ "dps").read[Seq[Map[String,Double]]] but dps in your JSON is not a Seq but a single entry - changing that part of the reader to (JsPath \ "dps").read[Map[String,Double]] will fix the problem.

Upvotes: 2

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