在java中使用super关键字继承变量 [英] Inheriting a variable using super keyword in java

问题描述

class Person
{
	String name;
	Person()
	{	
	}
	Person(String name)
	{
		this.name=name;
	}
}
class Employee extends Person
{
	void getdetails()
	{
		System.out.println("Name : "+super.name);
	}
}
class DoubtInSuper
{
	public static void main(String arr[])
	{
		Person p=new Person("Virat");
		Employee e=new Employee();
		e.getdetails();
	}
}

我的尝试：



以上程序的输出是 -

名称：null

What I have tried:

Output of the above Program is -
Name : null

推荐答案

麻烦的是你在这里创建了两个独立的实例： p 是一个实例，它是一个Person， e 是第二个单独的实例，以及它的'员工'。这两个实例没有以任何方式加入，因此 p 的情况不会发生在 e 。

想想看：你买了一辆车，把你的手机放在手套箱里。我给你搭乘我的梅赛德斯（延伸汽车，福特，布加迪和凯迪拉克等） - 您希望在我的手套箱中找到您的手机吗？

The trouble is that you have created two separate instances here: p is one instance, and it's a Person, e is a second separate instance, and its' an Employee. The two instances are not "joined" in any way, so what happens to p does not happen to e.
Think about it: you buy a Car, and put your mobile in the glove box. I give you a ride in my Mercedes (which extends Car, as does Ford, Bugatti, and Cadillac) - would you expect to find your mobile in my glove box?

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