day24 static

package com.oop.demo07;
//静态代码块
public class Person {
    {//2：赋初始值
        //代码块（匿名代码块）
        System.out.println("匿名代码块");
    }
    static {//1  只执行一次
        //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();


    }
}

package com.oop.demo07;

import com.sun.xml.internal.ws.api.model.wsdl.WSDLOutput;

//static
public class Student {
    //静态属性
    private static int age;//静态的变量
    private double score;//非静态变量
    //静态方法
    public void run(){

    }
    public static void go(){

    }

    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 com.oop.demo07;
//静态导入包
import static java.lang.Math.random;
import static java.lang.Math.PI;
public class Test {
    public static void main(String[] args) {
        System.out.println(random());
        System.out.println(PI);
    }
}

final之后不能继承