Java实例属性覆写问题

先看一段Python代码

实现效果是子类和父类共用一个 sayHello() 方法，通过覆写属性name 输出不同的属性

class Parent():
    name = "parent"

    def getName(self):
        return self.name

    def sayHello(self):
        print(self.name, "-", self.getName())


class Child(Parent):
    name = "child"


if __name__ == "__main__":
    parent = Parent()
    print(parent.getName())
    parent.sayHello()

    child = Child()
    print(child.getName())
    child.sayHello()

输出效果满足预期要求

parent
parent - parent
child
child - child

再来看Java代码

class Parent {
    private String name = "parent";

    public String getName() {
        return name;
    }

    public void sayHello() {
        System.out.println(name + " - " + getName());
    }
}

class Child extends Parent {
    private String name = "child";
}

public class Demo {
    public static void main(String[] args) {
        Parent parent = new Parent();

        System.out.println(parent.getName());
        parent.sayHello();

        Child child = new Child();
        System.out.println(child.getName());
        child.sayHello();
    }
}

输出结果和预期不一样

parent
parent - parent
parent
parent - parent

修改一下子类，覆写父类的getName()方法

class Parent {
    private String name = "parent";

    public String getName() {
        return name;
    }

    public void sayHello() {
        System.out.println(name + " - " + getName());
    }
}

class Child extends Parent {
    private String name = "child";

    // 增加方法覆写
    @Override
    public String getName() {
        return name;
    }
}

public class Demo {
    public static void main(String[] args) {
        Parent parent = new Parent();

        System.out.println(parent.getName());
        parent.sayHello();

        Child child = new Child();
        System.out.println(child.getName());
        child.sayHello();
    }
}

输出结果看到，通过覆写方法获取属性的方式可以获取子类属性，直接获取的属性还是父类中的属性

parent
parent - parent
child
parent - child