encode/decode json 的 Scala 3 + http4s 问题

Question

我有一个 Scala 3 项目（3.0.0 版），我正在尝试使用 http4s 构建简单的 Rest API。

我对 decoding/encoding JSON 有疑问。

我正在基于 http4s.g8.

构建我的代码

问题发生在 this line:

implicit val jokeDecoder: Decoder[Joke] = deriveDecoder[Joke]

编译错误：

no implicit argument of type deriving.Mirror.Of[com.example.quickstart.Jokes.Joke] was found for parameter A of method deriveDecoder in object semiauto

Scala 3 中是否有一些变化使其与众不同？

我的依赖关系

scalaVersion := "3.0.0"

val Http4sVersion = "0.23.6"
val CirceVersion = "0.14.1"

libraryDependencies ++= Seq(
  "org.http4s"      %% "http4s-blaze-server" % Http4sVersion,
  "org.http4s"      %% "http4s-blaze-client" % Http4sVersion,
  "org.http4s"      %% "http4s-circe"        % Http4sVersion,
  "org.http4s"      %% "http4s-dsl"          % Http4sVersion,

  "io.circe"        %% "circe-core"          % CirceVersion,
  "io.circe"        %% "circe-generic"       % CirceVersion
)

Answer 1

final case class Joke(joke: String) extends AnyVal

是cuprit。重写为

final case class Joke(joke: String)

它应该有效

encode/decode json 的 Scala 3 + http4s 问题

Scala 3 + http4s problem with encode/decode json

scala

scala-3

http4s