JAVA static关键字

static成员变量

public class Person {

    String name;
    static int age;

    Person() {
        System.out.println("Person 无参构造");
    }

    void eat() {
        System.out.println("Person 吃饭");
    }
}

也可以通过类名方式调用

public class Test {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Person person1 = new Person();
        Person person2 = new Person();

        person1.age = 12;
        System.out.println(person1.age);
        System.out.println(person2.age);
        
        Person.age = 13;
        System.out.println(person1.age);
        System.out.println(person2.age);
    }

}

运行结果

Person 无参构造
Person 无参构造
12
12
13
13

static成员函数

静态成员函数只能使用静态成员变量

public class Person {

    static String name;
    static int age;

    Person() {
        System.out.println("Person 无参构造");
    }

    static void eat() {
        System.out.println(name + " 在吃饭");
    }
}

public class Test {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Person.name = "furong";
        Person.eat();
    }

}

运行结果

furong 在吃饭