是否有很多在一个类的方法增加该类的对象的开销？ [英] Does having lots of methods on a class increase the overhead of that class's object?

问题描述

想象一下，我使用一个类来从数据库中带回的物品，比如

Imagine I am using a class to bring back items from a database, say

class BankRecord {

public int id;
public int balance;

public void GetOverdraft() {
...
}
public void MakeBankrupt(){
...
}

}

现在，会发生什么样使用这个是否有表现仅仅2种方法（如上）或100的方法，也许他们中的一些非常大的。

Now, what would happen to the performance of using this if there were just 2 methods (as above) or 100 methods, maybe some of them very large.

会实例化数以百计的这些对象的更糟糕，如果所有的方法是每个对象？这是C＃/ Java类型语言，但它是很好的了解所有的语言。

Would instancing hundreds of these objects be worse if all the methods were on each object? This is for c#/java type languages, but it would be good to know for all languages.

或者是很好的做法，有一个单独的类，执行所有对这些对象的行为，并保留对象作为纯数据类？

Or is it good practice to have a seperate class, to perform all the actions on these objects, and leave the object as a pure data class?

推荐答案

创建时，运行时不会重复代码一个对象的实例。只有创建实例时的成员字段在内存中分配的空间。出于这个原因，你不应该，除非你有其他的一些设计这样做的理由打造仅数据类。

The runtime does not duplicate the code when creating an instance of a object. Only the member fields are allocated space in memory when an instance is created. For this reason, you shouldn't be creating "data-only" classes unless you have some other design reason for doing so.

话虽这么说，还有其他的最好-practices原因，您可能不希望一类的方法众多（如上帝反对反模式）。

That being said, there are other best-practices reasons why you might not want a class with a multitude of methods (e.g. the God object anti-pattern).

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