斯卡拉2.11反射和说明（JAVA）与参数 [英] Scala 2.11 reflection and annotations (Java) with parameters

问题描述

我用Java编写一个简单的类级别注解：

I have a simple class-level annotation written in Java:

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface Collection {
    String name();
}

使用，如：

@Collection(name="mytable")
case class Foo(...)

我要反思的类斯卡拉2.11获取名称参数的值。我怎样才能得到这个信息？我到这里：

I need to introspect classes in Scala 2.11 to obtain the value of the name parameter. How can I get this info? I'm up to here:

val sym = currentMirror.classSymbol(Class.forName(fullName))
val anno = sym.annotations.head
val annoType = anno.tree.tpe  // I can get this...works
println(anno.tree.children.tail)  // prints List(name = "mytable")

我接近！我可以看到我的名字参数和它的值，但是这似乎并不像一个地图或任何友好访问。我怎样才能让我的标注的参数的值？

I'm close! I can see my name parameter and its value but this doesn't seem to be accessible like a Map or anything friendly. How can I get the value of my annotation's parameter?

推荐答案

树API实现产品，以获得元素了，所以这是怎样的一个哈克论证，但你可以得到你的元素：

The tree api implements product to get elements out, so this is kind of a hacky demonstration, but you can get out your element:

  println(anno.tree.children.last.productElement(1))  // prints "mytable"

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