classOf[T]           相当于Java 里的   T.class
obj.isInstanceOf[T]  相当于Java 里的   obj instanceof T
obj.asInstanceOf[T]  相当于Java 里的   (T)obj


obj.getClass  精确获取对象类型
classOf[x]    精确获取类型
== 比较类型



scala>  class Pet
defined class Pet

scala> class Cat extends Pet
defined class Cat

scala> val pet = new Pet
pet: Pet = Pet@77476fcf

scala> val cat = new Cat
cat: Cat = Cat@2b15ba1a

scala> pet.isInstanceOf[Pet]
res4: Boolean = true

scala> cat.isInstanceOf[Pet]
res5: Boolean = true

scala> cat.getClass == classOf[Pet]
res6: Boolean = false

scala> cat.getClass == classOf[Cat]
res7: Boolean = true





 scala中的classOf isInstanceOf asInstanceOf