instanceof操作符判断对象类型

　　

　　instanceof 的语法格式如下：

myobject instanceof ExampleClass

myobject：某类的对象引用

ExampleClass：某个类

 class Quadrangle{
     public static void draw(Quadrangle q) {
     }
 }

 class Square extends Quadrangle {

 }

 class Anything {

 }
 public class Parallelogram extends Quadrangle {

     public static void main(String[] args) {

         Quadrangle q = new Quadrangle();
         //判断父类对象是否为Parallelogram子类的一个实例
         if(q instanceof Parallelogram) {
             Parallelogram p = (Parallelogram) q;
         }
         if(q instanceof Square){
             Square s = (Square)q;
         }
     }

 }