学习视频:https://www.bilibili.com/video/BV18J411W7cE?p=106&spm_id_from=pageDriver
创建一个学生类:
package Demo;
public class Student {
String name ;
int age ;
public void Study() {
System.out.println("学习");
}
public void doHomework() {
System.out.println("做作业");
}
}
测试类:
package Demo;
public class studentDemo {
public static void main(String[] args) {
Student girl = new Student();
girl.name = "小月月" ;
girl.age = 18;
System.out.println(girl.name);
girl.doHomework();
}
}
对象内存图:
单个对象:
多个对象:
两个学生对象的堆内存地址不同
调用s2的方法时,堆内存地址为002
多个对象指向同一个堆内存:
代码:
package Demo;
public class studentDemo {
public static void main(String[] args) {
Student girl = new Student() ;
Student boy = new Student() ;
System.out.println(girl) ;
System.out.println(boy) ;
girl.name = "小月月" ;
girl.age = 18 ;
System.out.println(girl.name+girl.age) ;
System.out.println(boy.name+boy.age) ;
boy = girl ;
System.out.println("========================================");
System.out.println(girl) ;
System.out.println(boy) ;
boy.name = "小强" ;
boy.age = 19 ;
System.out.println(girl.name+girl.age) ;
System.out.println(boy.name+boy.age) ;
girl.doHomework() ;
}
}
成员变量和局部变量:
成员变量:类中方法外的变量
局部变量:方法中的变量
二者区别: