Java学习第十九节之static关键字详解

static关键字详解

package oop.demo07;

//static ：
public class Student {

    private static int age;//静态的变量   多线程！
    private  double score;//非静态的变量

    public void run(){

    }

    public static void go(){

    }

    public static void main(String[] args) {
        go();

    }

}
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package oop.demo07;

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

    //1：只执行一次~
    static {
        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();

    }


}

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package 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(Math.random());
        System.out.println(PI);
    }



}

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