解决方法
您可以使用
shapeless执行此操作：
import shapeless._
import shapeless.ops.hlist._
// Trims if passed a String value,otherwise returns the value unchanged
object Trimmer extends Poly1 {
implicit val stringTrim = at[String] { _.trim }
implicit def noop[T] = at[T] { identity }
}
// Uses a Generic to transform the instance into an HList,maps over it
// and convert it back into the case class
def trimCaseClass[C,H <: HList](c: C)
(implicit g: Generic.Aux[C,H],m: Mapper.Aux[Trimmer.type,H,H]): C = {
val hlist = g.to(c)
val trimmed = hlist.map(Trimmer)
g.from(trimmed)
}
然后：
scala> case class A(s1: String,s2: String,i: Int)
defined class A
scala> val a = A(" 1 ","2",3)
a: A = A( 1,2,3)
scala> trimCaseClass(a)
res0: A = A(1,3)
