java 重载方法：两种方法具有相同的擦除
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/43442515/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Overloading a method: both methods have same erasure
提问by parsecer
I have the following code and it doesn't work: the error both methods have same erasureappears.
我有以下代码但它不起作用：both methods have same erasure出现错误。
public class Foo<V> {
public static void main(String[] args) {
}
public void Bar(V value) {
}
public void Bar(Object value) {
}
}
Also I have this code:
我也有这个代码：
public class Foo<V> {
public static void main(String[] args) {
}
public void Bar(B value) {
}
public void Bar(A value) {
}
}
class A {
}
class B extends A {
}
And this works. In the first case Vis a child of Object, just like in the second case Bis a child of A. Then why the first case results in error, while the second compiles successfully?
这有效。在第一种情况下V是 的孩子Object，就像在第二种情况下B是 的孩子一样A。那为什么第一种情况会出错，而第二种情况编译成功呢？
EDIT: What should I do to achieve method overloading, without raising an error?
编辑：我应该怎么做才能实现方法重载而不引发错误？
回答by Andy Turner
What should I do to achieve method overloading, without raising an error?
我应该怎么做才能实现方法重载而不引发错误？
Simple: don't try to overload the method with parameters with the same erasure.
简单：不要尝试使用具有相同擦除的参数重载方法。
A few options:
几个选项：
- Just give the methods different names (i.e. don't try to use overloading)
- Add further parameters to one of the overloads, to allow disambiguation (ideally only do this if you actually needthose parameters; but there are examples in the Java API where there are junk parameters simply to avoid overloading issues).
Bound the type variable, as suggested by @Kayaman:
<V extends SomethingOtherThanObject>
- 只需给方法不同的名称（即不要尝试使用重载）
- 向重载之一添加更多参数，以允许消除歧义（理想情况下，仅在您确实需要这些参数时才这样做；但 Java API 中有一些示例，其中存在垃圾参数只是为了避免重载问题）。
按照@Kayaman 的建议绑定类型变量：
<V extends SomethingOtherThanObject>
回答by Kayaman
Visn't "a child of Object". Vis an unbounded generic type that erases to Object, resulting in the error. If the generic type were bounded, such as <V extends Comparable<V>>, it would erase to Comparableand you wouldn't get the error.
V不是“的孩子Object”。V是一个无界泛型类型，它擦除为Object，从而导致错误。如果泛型类型是有界的，例如<V extends Comparable<V>>，它将擦除到Comparable并且您不会收到错误。
