小编jwi*_*der的帖子

我一直在使用Scala进行Manifest等实验,当我通过getDeclaredFields方法访问时,我很难找到使用对象字段的方法......

这是一个例子:

class Woah(val x: String, val y: String)

val w = new Woah("w_x", "w_y")
classOf[Woah].getDeclaredFields foreach (field => println(field.get(w))

我尝试了很多变体,比如在类Woah中创建一个方法,它执行与第三行代码相同的操作,但用field.get(this)替换field.get(w),它显示了相同的异常.抛出的异常是:

java.lang.IllegalAccessException: Class Fun$Woah$$anonfun$1 can not access a member of class Fun$Woah with modifiers "private final"
    at sun.reflect.Reflection.ensureMemberAccess(Reflection.java:65)
    at java.lang.reflect.Field.doSecurityCheck(Field.java:960)
    at java.lang.reflect.Field.getFieldAccessor(Field.java:896)
    at java.lang.reflect.Field.get(Field.java:358)
    at Fun$Woah$$anonfun$1.apply(Fun.scala:17)
    at Fun$Woah$$anonfun$1.apply(Fun.scala:17)
    at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:34)
    at scala.collection.mutable.ArrayOps.foreach(ArrayOps.scala:35)
    at Fun$Woah.<init>(Fun.scala:17)
    at Fun$.main(Fun.scala:20)
    at Fun.main(Fun.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at scala.tools.nsc.util.ScalaClassLoader$$anonfun$run$1.apply(ScalaClassLoader.scala:81)
    at scala.tools.nsc.util.ScalaClassLoader$class.asContext(ScalaClassLoader.scala:24)
    at scala.tools.nsc.util.ScalaClassLoader$URLClassLoader.asContext(ScalaClassLoader.scala:86)
    at scala.tools.nsc.util.ScalaClassLoader$class.run(ScalaClassLoader.scala:81)
    at scala.tools.nsc.util.ScalaClassLoader$URLClassLoader.run(ScalaClassLoader.scala:86)
    at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:83)
    at …