在Java中调用子类的方法 [英] Call a method of subclass in Java
问题描述
如果我有基类
Base thing = null;
其中有一个子类
class Subclass扩展Base
我将其作为
thing = new Subclass
如何调用一个特别在Subclass中但不在Base中的方法？
ex。
基本只有方法（）
子类有方法（）和 specialMethod（）
方法 specialMethod（）是我要调用的那个。
If I have a base class
Base thing = null;
of which there is a subclass
class Subclass extends Base
and I instigate it as
thing = new Subclass
how would I call a method that is specifically in Subclass, but not in Base?
ex.
Base has only method()
Subclass has method() and specialMethod()
the method specialMethod() is the one I want to call.
推荐答案
其他人已经提到了如何投射对象以获得问题的答案，但首先要求提出问题指出可能的设计问题。一些可能的原因：
The others have already mentioned how to cast objects to get an answer to your question, but asking that question in the first place points to a possible design problem. Some possible reasons:
- 该方法位置错误。
- 调用该方法的代码方法是在错误的地方。
- 子类不应该扩展另一个类。最好首选组合而不是继承。在继承时，代码应遵循 Liskov替换原则。
- 这些课程是非一致性，他们不仅仅是一个责任，它们应分成多个类。
- The method is in the wrong place.
- The code which calls the method is in the wrong place.
- The subclass should not extend the other class. It's best to prefer composition over inheritance. And when inheriting, the code should follow the Liskov substitution principle.
- The classes are non-cohesive, they have more than one responsibility, and they should be split into multiple classes.
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