Java:继承构造函数 [英] Java: Inherit constructor
问题描述
我希望有一个构造函数,其参数可以自动由所有子类继承,但Java不允许我这样做
I want to have a constructor with an argument that gets inherited by all child classes automatically, but Java won't let me do this
class A {
public A(int x) {
// Shared code here
}
}
class B extends A {
// Implicit (int x) constructor from A
}
class C extends A {
// Implicit (int x) constructor from A
}
我不想要必须为每个子类编写 B(int x)
, C(int x)
等。有没有更聪明的方法来解决这个问题?
I don't want to have to write B(int x)
, C(int x)
, etc. for each child class. Is there a smarter way of approaching this problem?
解决方案#1。创建一个 init()
方法,该方法可以在构造函数之后调用。这是有效的,虽然对于我的特定设计,我想要求用户在构造函数中指定在编译时验证的某些参数(例如,不通过varargs / reflection)。
Solution #1. Make an init()
method that can be called after the constructor. This works, although for my particular design, I want to require the user to specify certain parameters in the constructor that are validated at compile time (e.g. Not through varargs/reflection).
推荐答案
你做不到。如果你想在你的基类中有一个参数化的构造函数 - 而且没有无参数的构造函数 - 你必须在每个构造函数中定义一个构造函数(并调用 super()
构造函数)。后裔类。
You can't. If you want to have a parameterized constructor in your base class - and no no-argument constructor - you will have to define a constructor (and call super()
constructor) in each of descendant classes.
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