static学习

package com.tu.oop.demo7;

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

    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);
        s1.run();
        go();

    }
}
=====================================================

package com.tu.oop.demo7;

public class Person {
    {
        //代码块（匿名代码块）:第二步执行(赋初始值)
        System.out.println("匿名代码块");
    }
    static {
        //静态代码块:第一步执行(只执行一次)
        System.out.println("静态代码块");
    }
    //构造方法:第三步执行
    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();
    }
}
==================================================

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);
    }
}