Given an example JSON object with a nested object who's properties are unkown:
{ "Key":"01234",
"eventProperties":{
"unknownProperty1":"value",
"unknownProperty2":"value",
"unknownProperty3":"value"
},
}
I have tried to use json4s' extract function with the following case class (In Scala):
case class nestedClass(Key:String, eventProperties:Map[(String,Any)])
Which results in the following error:
org.json4s.package$MappingException: Can't find constructor for nestedClass
Is it possible to do this without defining every possible property of eventProperties?
Update: there was a bug in json4s 3.2.10 causing this issue - updating to 3.2.11 and extracting to Map[String,Any] works fine.
I'm not sure what you are doing to get the exception you have posted, but the following works (note a Map instead of List):
import org.json4s._
import org.json4s.jackson.JsonMethods._
import org.json4s.DefaultFormats
val json = parse("""
{ "key":"01234",
"eventProperties":{
"unknownProperty1":"value",
"unknownProperty2":"value",
"unknownProperty3":"value"
}
}
""")
case class NestedClass(key:String, eventProperties:Map[String,Any])
implicit val formats = DefaultFormats
json.extract[NestedClass]
In Order to get eventProperties as List[(String, Any)], your json should be,
""" {
"key": "01234",
"eventProperties": [
{"unknownProperty1": "value"},
{"unknownProperty2": "value"},
{"unknownProperty3": "value"}
]
}"""
Otherwise, you can use Map instead of List as
case class nestedClass1(key:String, eventProperties:Map[String,Any]) and then convert to nestedClass as nestedClass( n1.key, n1.eventProperties.toList)
