Java 父类可以调用子类方法吗？
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Can a Parent call Child Class methods?
提问by Kevin Boyd
Referring here
参考这里
A is a precompiled Java class (I also have the source file)
B is a Java class that I am authoring
B extends A.
A 是预编译的 Java 类（我也有源文件） B 是我正在创作的 Java 类
B 扩展 A。
How can logic be implemented such that A can call the methods that B has.
The following are the conditions:
如何实现逻辑，使 A 可以调用 B 拥有的方法。
以下是条件：
- I don't want to touch A(only as a last option though that is if no other solution exists).
- I don't want to use reflection.
- 我不想触摸 A（仅作为最后一个选项，但如果不存在其他解决方案）。
- 我不想使用反射。
As stated, if needed I could modify A. What could be the possible solution either way?
如上所述，如果需要，我可以修改 A. 两种可能的解决方案是什么？
采纳答案by Alex Martelli
Class Ashould define the methods it's going to call (probably as abstract ones, and A should be an abstract class, per Paul Haahr's excellent guide); Bcan (in fact to be concrete MUST, if the method are abstract) override those methods. Now, calls to those methods from other methods in A, when happening in an instance of class B, go to B's overrides.
类A应该定义它要调用的方法（可能是抽象的，A 应该是一个抽象类，根据 Paul Haahr 的优秀指南）；B可以（实际上是具体的必须，如果方法是抽象的）覆盖这些方法。现在，从 中的其他方法调用这些方法A，当在类 B 的实例中发生时，转到 B 的覆盖。
The overall design pattern is known as Template Method; the methods to be overridden are often called "hook methods", and the method performing the calls, the "organizing method".
整体设计模式称为模板方法；要覆盖的方法通常称为“挂钩方法”，执行调用的方法称为“组织方法”。
回答by San Jacinto
I would be rather hesitant to do this. Please correct me if I am wrong and then I will delete, but it sounds like you want to maintain an A object along with a B object. If they indeed are not the same object, the "tying together" (that's a scientific term) you'll have to do would be pretty ugly.
我会很犹豫要不要这样做。如果我错了，请纠正我，然后我将删除，但听起来您想同时维护一个 A 对象和一个 B 对象。如果它们确实不是同一个对象，那么您必须做的“捆绑在一起”（这是一个科学术语）将非常难看。
回答by Timmmm
Yes it seems that if you override the super/base-classes's functions, calls to those functions inthe base class will go to the child/derived class. Seems like a bad design in my opinion, but there you go.
是的，它看来，如果你重写超/基类的函数，这些函数的调用在基类中必去的孩子/派生类。在我看来，这似乎是一个糟糕的设计，但你去了。
class Base
{
public void foo()
{
doStuff();
}
public void doStuff()
{
print("base");
}
}
class Derived extends Base
{
@Override
public void doStuff()
{
print("derived");
}
}
new Derived().foo(); // Prints "derived".
Obviously all of Derived's methods have to be already defined in Base, but to do it otherwise (without introspection) would be logically impossible.
显然， 的所有Derived方法都必须已经在 中定义Base，但否则（没有自省）在逻辑上是不可能的。
