Java面向对象

Java面向对象 静态方法与非静态方法

静态方法

public class Student {
    public static void say(){
    	System.out.println("学生说话了");
	}
}
public class Demo1{
    
    public static void main(String[] args){
    	Student.say(); //可直接调用
	}
}

非静态方法

public class Student {
    public void say(){
    	System.out.println("学生说话了");
	}
}
public class Demo2{
    
    public static void main(String[] args){
    	//实例化这个类 new
        //对象类型 对象名 = 对象值
        Student student = new Student();
        
        student.say();
	}
}

值传递与引用传递

值传递

package com.oop.demo01;

public class PassByValue {
    public static void main(String[] args) {
        int a = 1;
        System.out.println(a);

        PassByValue.change(a);

        System.out.println(a);  //1
    }

    //值传递
    public static void change(int a){
        a = 10;
    }

}

引用传递

package com.oop.demo01;

public class PassByReference {
    public static void main(String[] args) {
        Person person1 = new Person();

        System.out.println(person1.name);   //null

        PassByReference.change(person1);

        System.out.println(person1.name);   //BIT0
    }

    //引用传递 传入参数是Person类中的person1对象，可以改变他的属性！
    public static void change(Person person){
        person.name = "BIT0";
    }

}
class Person{
    String name;    //null
}