我可以对Number基类进行算术运算吗？ [英] Can I do arithmetic operations on the Number baseclass?

问题描述

我正在尝试在Java中创建一个将对数字执行操作的泛型类。在以下示例中，添加如下：

I am trying to create a generic class in Java that will perform operations on numbers. In the following example, addition, as follows:

public class Example <T extends Number> {

    public T add(T a, T b){
        return a + b;
    }

}

原谅我的天真，因为我是相对的Java泛型的新手。此代码无法使用错误进行编译：

Forgive my naivety as I am relatively new to Java Generics. This code fails to compile with the error:

参数类型的运算符+未定义T，T

The operator + is undefined for the argument type(s) T, T

我认为通过添加extends Number，代码将被编译。是否可以执行此Java或我是否必须为每个Number类型创建重写方法？

I thought that with the addition of "extends Number" the code would compile. Is it possible to do this Java or will I have to create overridden methods for each Number type?

推荐答案

数字没有+运算符与它关联，也不能，因为没有运算符重载。

Number does not have a + operator associated with it, nor can it since there is no operator overloading.

虽然会很好。

基本上，你要求java自动装备一个数字的目标，其中包括Integer，Float和Double，它们可能被自动装箱并且应用了一个加号运算符，但是，可能有任何数量的其他未知的数字后代不能自动装箱，直到运行时才能知道。 （该死的擦除）

Basically, you are asking java to autobox a descedant of Number which happens to include Integer, Float and Double, that could be autoboxed and have a plus operator applied, however, there could be any number of other unknown descendants of Number that cannot be autoboxed, and this cannot be known until runtime. (Damn erasure)

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