How to convert Json objects into arrays [(string, double)] in Scala JSON4s? - json

Question

I don't know how to use CustomSerializer to convert JSON to Scala data
I don't need to serialize the parts, but deserialization is difficult
Can someone help me? Thank you very much
{
"parameters": {
"field_owner": true,
"sample_field": "gender",
"sample_strategy": "by_ratio",
"sample_config": [["male", 1500.0], ["female", 1500.0]],
"with_replacement": true,
"random_seed": 114514,
"least_sample_num": 100
},
"input_artifacts": {"dataset": {"object_id": "upload/ml_classifier_predict_result"}},
"output_artifacts": {"predict_result": {"object_id": "ingest_output.csv"}}
}
class TupleSerializer extends CustomSerializer[(String,Double)](tuple_formats => (
{
case JArray(List(JString(x), JDouble(y))) =>
(x,y)
},{
case x:Tuple2[String,Double] => null
}
))
implicit val formats: Formats = DefaultFormats + new TupleSerializer
val fileBuffer = Source.fromFile(path)
val jsonString = fileBuffer.mkString
parse(jsonString).extract[StratifiedSampleArgument]
}
error message：
o usable value for parameters
No usable value for sample_config
Expected object with 1 element but got JArray(List(JString(male), JDouble(1500.0)))
at com.alipay.morse.sgxengine.driver.StratifiedSampleDriverTest.main(StratifiedSampleDriverTest.scala:15)
Caused by: org.json4s.package$MappingException:
No usable value for sample_config
Expected object with 1 element but got JArray(List(JString(male), JDouble(1500.0)))
at com.alipay.morse.sgxengine.driver.StratifiedSampleDriverTest.main(StratifiedSampleDriverTest.scala:15)
Caused by: org.json4s.package$MappingException: Expected object with 1 element but got JArray(List(JString(male), JDouble(1500.0)))
at com.alipay.morse.sgxengine.driver.StratifiedSampleDriverTest.main(StratifiedSampleDriverTest.scala:15)
[INFO]
[INFO] Results:
[INFO]
[ERROR] Errors:
[ERROR] StratifiedSampleDriverTest.main:15 » Mapping No usable value for parameters
No...
[INFO]
[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0