从泛型类获取类名和属性名 [英] Obtaining class name and property names from generic class

问题描述

考虑以下代码:

trait GeneralTrait[T] {
   def getClassName() = ???
   def params() = ???
}

case class SomeClass(id: Long, name: String)

class ConcreteClass extends GeneralTrait[SomeClass]

是否可以让 getClassName() 返回一个 String 'SomeClass' 并使 params() 返回一个列表 ['id', 'name'] ?

Is it possible to make getClassName() return a String 'SomeClass' and to make params() return a list ['id', 'name'] ?

推荐答案

我建议你总是使用 scala 反射而不是 java 反射.类和方法的名称在编译过程中往往会出现一些乱码.Java 不知道 scala，所以它总是会给你乱码.

I would advise you to always use scala reflection instead of java reflection. Names of classes and methods tend to get garbled a bit during compilation. Java doesn't know scala so it will always give you the garbled names.

如果您想了解有关类型参数的信息，无论如何您都必须使用 Scala 反射.

If you want information about type parameters you will have to use scala reflection anyway.

scala> :paste
// Entering paste mode (ctrl-D to finish)

import scala.reflect.runtime.universe.{TypeTag, typeOf}

trait GeneralTrait[T] {
   def getClassName()(implicit tag: TypeTag[T]) = typeOf[T].typeSymbol.name.toString
   def params()(implicit tag: TypeTag[T]) = typeOf[T].typeSymbol.asClass.primaryConstructor.asMethod.paramLists.flatten.map(_.name.toString)
}

case class SomeClass(id: Long, name: String)

class ConcreteClass extends GeneralTrait[SomeClass]

// Exiting paste mode, now interpreting.


scala> val c = new ConcreteClass
c: ConcreteClass = ConcreteClass@64d776b6

scala> c.getClassName
res0: String = SomeClass

scala> c.params
res1: List[String] = List(id, name)

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