circe

问题 I've seen similar questions before, but none of them have worked. I think that they ask something different so I'm asking here. I have something like this in one file: sealed trait Thing case class SomeThing() extends Thing case class OtherThing() extends Thing and in another file: val str = //valid json val decoded = decode[Thing](str) println(decoded) and I get: Left(DecodingFailure(...)) This works if I did: val str = //valid json val decoded = decode[SomeThing](str) println(decoded) 回答1:

问题 Suppose I want to decode some values from a JSON array into a case class with circe. The following works just fine: scala> import io.circe.generic.auto._, io.circe.jawn.decode import io.circe.generic.auto._ import io.circe.jawn.decode scala> case class Foo(name: String) defined class Foo scala> val goodDoc = """[{ "name": "abc" }, { "name": "xyz" }]""" goodDoc: String = [{ "name": "abc" }, { "name": "xyz" }] scala> decode[List[Foo]](goodDoc) res0: Either[io.circe.Error,List[Foo]] = Right(List

来源： https://stackoverflow.com/questions/54049082/convert-json-to-a-mapstring-string

来源： https://stackoverflow.com/questions/63726122/how-to-read-json-out-of-doobie-scala-postgresql-database-with-circe

来源： https://stackoverflow.com/questions/63726122/how-to-read-json-out-of-doobie-scala-postgresql-database-with-circe

来源： https://stackoverflow.com/questions/63644845/postgresql-error-with-doobie-psqlexception-the-column-index-is-out-of-range-3

问题 I am learning Circe and Scala for a project at work. To explain my issue, start with the following example: import io.circe.syntax._ object TestDrive extends App { val labels = Seq("Banana", "Banano", "Grapefruit") println(labels.asJson) } Ok so this outputs: ["Banana","Banano","Grapefruit"] This is good. Now I want to make my code a bit more general. I want to write a function that takes in a Sequence, whose elements can be of type AnyVal. Here is my attempt: import io.circe.syntax._ import

问题 I am learning Circe and Scala for a project at work. To explain my issue, start with the following example: import io.circe.syntax._ object TestDrive extends App { val labels = Seq("Banana", "Banano", "Grapefruit") println(labels.asJson) } Ok so this outputs: ["Banana","Banano","Grapefruit"] This is good. Now I want to make my code a bit more general. I want to write a function that takes in a Sequence, whose elements can be of type AnyVal. Here is my attempt: import io.circe.syntax._ import

问题 As per the question, how to encode Map[String, MyCaseClass] into Seq[String, String] using circe? Model: case class MyCaseClass(name: String, enabled: Boolean) case class Parent(parentName: String, collection: Map[String, MyCaseClass]) Parent( "parent-name", Map( "external-name-a", MyCaseClass("internal-name-a", true), "external-name-b", MyCaseClass("internal-name-b", false) ) ) I'd like to encode this into a: Seq[name = <map key>, enabled = <boolean value from MyCaseClass>] For example: { ..

问题 Given this recursive type grammar: case class Fix[F[_]](out: F[Fix[F]]) type FieldValue = Seq[String] :+: String :+: Int :+: Long :+: CNil type FieldLeaf[F] = FieldValue :+: SubField[F] :+: CNil type SubField[F] = Seq[F] type Field0[F] = (String, FieldLeaf[F]) type Field = Fix[Field0] And instances of Seq[Field] Is it feasible to instantiate concrete classes from the type grammar? I.e: def instantiate[T](fields:Seq[Field]):Option[T] = .... case class Person(id:Long, name:String) val fields