可以避免在Java中对super()的默认调用吗? [英] Possible to avoid default call to super() in Java?

问题描述

假设出于某种原因，我不想隐式调用super()，这在默认情况下是完成的.

Assume for some reason that I don't want to implicitly call super() which is done by default.

class Animal {
    public Animal() {
        System.out.println("Constructing an animal.");
    }
}
class Dog extends Animal {
    public Dog() {
        System.out.println("Constructing a dog.");
    }
    public static void main(String[] a) {
        new Dog();
    }
}

有什么方法可以禁用"创建新Dog时调用的默认行为?还是在原理和概念上是错误的?

Is there any way to "disable" the default behavior that super() is invoked when making a new Dog? Or would that be principally and conceptually wrong?

我的意思是，在某些情况下，您可能只希望子类的构造函数而不调用基类的构造，而仍然继承基类.

I mean there could be cases where you would want only the constructor of the subclass and not invoke the construction of the baseclass, and still inherit the baseclass.

推荐答案

如果我正确理解了您想覆盖Animal构造函数的行为，或者只是不调用它.如果是这样，那么您在概念上是错误的:您始终需要调用一个超级构造函数，您唯一可以进行的调用就是提供一个非默认的构造函数，即一个带有参数并提供适当的参数以影响该构造函数的行为(例如，通过选择其他构造函数，传递某种策略/功能对象等).

If I understand you correctly you want to override the behavior of the Animal constructor or just not call it. If so you're conceptually wrong: you always need to call a super constructor, the only thing you could to with the calls is provide a non-default constructor, i.e. one with arguments and provide appropriate arguments to influence the behavior of that constructor (e.g. by either selecting a different constructor, passing some sort of strategy/function object etc.)

另一种方法可能是提供默认构造函数正在调用的某些init()方法，您可以对其进行覆盖，但是存在一些问题，例如:

Another way might be to provide some init() method that the default constructor is calling and which you can override but there are a few problems with it, e.g.:

• 如果重写的方法尝试访问仅对子类可见的任何内容(例如，其他字段)，您可能会遇到问题，因为尚未初始化.
• 该方法无法初始化任何final字段.

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