Java学习day12

狂神说Java

面向对象14：static关键字详解

package oop.demo07;

//static
public class Student {
    private static int age;//静态的变量
    private double score;//非静态的变量

    public static void main(String[] args) {
        Student s1 = new Student();
        System.out.println(Student.age);
        System.out.println(s1.age);
        System.out.println(s1.score);
    }
}

package oop.demo07;

public class Person {
    //2
    {
        //代码块 （匿名代码块）
        System.out.println("匿名代码块");
    }
    
    //1
    static {
        //静态代码块
        System.out.println("静态代码块");
    }
    
    //3
    public Person(){
        System.out.println("构造方法");
    }

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

}

package oop.demo07;

public class Person {
    //2：赋初始值~
    {
        //代码块 （匿名代码块）
        System.out.println("匿名代码块");
    }

    //1 : 只执行一次
    static {
        //静态代码块
        System.out.println("静态代码块");
    }

    //3
    public Person(){
        System.out.println("构造方法");
    }

    public static void main(String[] args) {
        Person person1 = new Person();
        System.out.println("====================");
        Person person2 = new Person();
    }

}