java面向对象：instanceof和static关键字

instanceof

instanceof 判断对象类型是否一致

Object o = new Student();
        System.out.println(o instanceof Student);
        System.out.println(o instanceof Person);
        System.out.println(o instanceof Object);
        System.out.println(o instanceof Thread);
        System.out.println(o instanceof String);
        Person person = new Student();
        System.out.println(person instanceof Student);
        System.out.println(person instanceof Person);
        System.out.println(person instanceof Object);
        /*System.out.println(person instanceof Thread);
        System.out.println(person instanceof String);*/

static关键字

package com.oop.demo7;

/**
 * 先后顺序：静态代码块 匿名代码块 空构造    静态代码块只被加载一次
 * 加了static的方法只能调用加了static的方法 ，没加static的方法都能调用
 * 因为加了static的属性或方法是在类加载的时候就被创建，那时候非静态方法还没有被加载，所以不能调用非静态方法
 */
public class Person {
    public static String name;
    public String age;
    {
        System.out.println("匿名代码块");
    }
    static {
        System.out.println("静态代码块");
    }
    public Person(){
        System.out.println("空构造");
    }
    public static void say(){
    }
    public void hello(){

    }

    public static void main(String[] args) {
        Person person = new Person();
        Person person1 = new Person();
        
    }
}