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Lindenes
Asked: 2025-02-13 04:47:10 +0800 CST

关于scala：DTO的Scala案例类对话(无形)

  • 772

我想将案例类 UserDTO 转换为案例类 User 我在无形案例类转换中找到了解决方案

class SameFieldConverter[T] {
def apply[S, SR <: HList, TR <: HList, MR <: HList, IR <: HList](s: S)(implicit
  genS: LabelledGeneric.Aux[S, SR],
  genT: LabelledGeneric.Aux[T, TR],
  merger: Merger.Aux[SR, HNil, MR],
  intersection: Intersection.Aux[MR, TR, IR],
  align: Align[IR, TR]) = genT.from(intersection(merger(genS.to(s), HNil)))

但是我对不同的字段有问题，例如在 UserDTO 中我有字段名称、姓氏，但在 User 中我有全名。

  case class UserDTO(name:String, surname:String, age:Int){
    def toDomain:User = User(name + surname, age)
  }
  case class User(fullName:String, age:Int)

另外，我对不同的字段名称也有问题，例如姓名 -> 姓氏

case class UserDTO(name:String, surname:String, age:Int)
case class User(firstName:String, surname:String, age:Int)

我想到的解决方案就像在羽毛笔别名（“name”，_.surname）中一样，但我的脑子很小。我还考虑过研究使用 scala 反射 API

scala

1 个回答

  1. Best Answer

    如果您只是想将一个案例类转换为另一个案例类，并且这两个案例类具有相同或相似的字段，我认为shapeless有点过头了。对于这样的情况，我会选择chimney。代码应该看起来像

    • build.sbt
    libraryDependencies += "io.scalaland" %% "chimney" % "1.7.3"
    • Transformer.scala
    import io.scalaland.chimney.dsl._

case class UserDTO(name:String, surname:String, age:Int)
case class User(firstName:String, surname:String, age:Int)

class Transformer {
  def fromUserDtoToUser(userDTO: UserDTO): User = {
    userDTO
      .into[User]
      .withFieldComputed(_.firstName, _.name) // here is the mapping between fields with different names
      .transform
  }
}

    虚拟主方法应如下所示

    • Main.scala
    object Main {
  def main(args: Array[String]): Unit = {
    val transformer = new Transformer
    val userDTO = UserDTO("john", "doe", 30)
    val user = transformer.fromUserDtoToUser(userDTO)
    println(userDTO)
    println(user)
  }
}

    输出将是

    UserDTO(     name = john, surname = doe, age = 30)
User(   firstName = john, surname = doe, age = 30)
    • 4

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