Java基础-20、instanceof：判断是否是某种类型的实例

是Java的一种运算符。用法：

a instanceof A;//a是A的实例就返回true否则返回false

举例如下： 类A继承了类B和接口Comparable,并且类A必定继承了Object所以输出全为true

import java.util.ArrayList; public class text{ public static void main(String[] args) { A xiaoli=new A("xiaoli",10); System.out.println(xiaoli instanceof A); System.out.println(xiaoli instanceof name); System.out.println(xiaoli instanceof Object); System.out.println(xiaoli instanceof Comparable); } } class name { private String m_name; public name(String m_name) { this.m_name=m_name; } public void display() { System.out.println(m_name); } } class A extends name implements Comparable<A> { private int size; public A(String name,int size) { super(name); this.size=size; } @Override public int compareTo(A o) { if(this.size==o.size) { return 0; } else if(this.size<o.size) { return -1; } else { return 1; } } }