使用反射调用Scala构造函数的参数数量错误

但是,我遇到IllegalArgumentException,提示错误的参数数量.

考虑以下：

case class Vec2(x: Float,y: Float)

object TestApp {
  def main(args: Array[String]) {
    //after some research I found the last constructor always to be the default
    val ctor = classOf[Vec2].getConstructors.last

    println("ctor = " + ctor)
    println("takes parameters: " + ctor.getParameterTypes.length)

    val params = new Array[Float](2)

    params.update(0,1.0f)
    params.update(1,-1.0f)

    println("num parameters: " + params.length)

    println("trying to create new instance...")
    try {
      val x = ctor.newInstance(params)
      println("new instance: " + x)
    }
    catch {
      case ex => ex.printStackTrace
    }
  }

输出如下：

ctor = public pd.test.Vec2(float,float)
takes parameters: 2
num parameters: 2
trying to create new instance...
java.lang.IllegalArgumentException: wrong number of arguments
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at pd.test.TestApp$.main(TestApp.scala:60)
    at pd.test.TestApp.main(TestApp.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:115)

我曾经在Java中经历过类似的事情.在这种情况下,我试图实例化的类是另一个类的内部类,因此Java期望一个隐式的附加参数,它是封闭类的Class对象(如果该类被声明为静态),或者是一个实例封闭的班级.

但是,在这种情况下,没有封闭的Vec2类,除非Scala在内部添加一个(尽管java.lang.Class.getEnclosingClass()为我返回null).

所以我的问题是如何使用反射实例化Scala类？是否存在Scala构造函数隐含的其他参数？