instanceof instanceof是Java的一個(gè)二元操作符，和==，>，<是同一類(lèi)東西。由于它是由字母組成的，所以也是Java的保留關(guān)鍵字。它的作用是測(cè)試它左邊的對(duì)象是否是它右邊的類(lèi)的實(shí)例，返回boolean類(lèi)型的數(shù)據(jù)。舉個(gè)例子：
String s = "I AM an Object!";
boolean isObject = s instanceof Object;
給出個(gè)例題： class Animal{
public String name ;
public Animal(String name){
this.name=name;
}
}
class Dog extends Animal{
public String furcolor;
public Dog(String n,String furcolor){
super(n);this.furcolor=furcolor;
}
}
class Cat extends Animal{
public String eyecolor;
public Cat(String n,String eyecolor){
super(n);this.eyecolor=eyecolor;
}
}
public class Test{
public static void main(String args[]){
Animal a= new Animal("name");
Cat cat=new Cat("xiaohua","blue");
Dog dog=new Dog("xiaohuang","Yellow");
System.out.println(a instanceof Animal);
System.out.println(cat instanceof Animal);
System.out.println(dog instanceof Animal);
System.out.println(a instanceof Cat);
a=new Dog("BigYellow","Yellow");
System.out.println(a.name);
Dog b=(Dog)a;
System.out.println(b.furcolor);
}
}
Tags -
java
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