java和c＃中泛型的语法区别(syntax difference between generics in java and c#)

java和c＃中泛型的语法区别(syntax difference between generics in java and c#)

我来自AC＃背景，与c＃相比，泛型如何看待java？ （基本用法）

I'm coming from a c# background, how do generics look in java compared to c#? (basic usage)

最满意答案

这是一个相当大的问题，说实话 - 最大的区别不在于语法，而在于行为......在这一点上，他们真的非常不同。

我建议你阅读Sun的泛型教程和Angelika Langer的Java泛型常见问题解答 。 尽管从C＃/ .NET首先尽可能地忘掉你对泛型的所有知识。 具体来说，尽管.NET泛型类型在执行时保留了类型参数，但Java泛型并不是由于类型擦除 。

换句话说，在C＃中，您可以编写：

public class GenericType<T> { public void DisplayType() { Console.WriteLine(typeof(T)); } }

...你不能在Java中做到这一点:(

此外，.NET泛型可以具有值类型类型参数，而Java泛型不能（因此您必须使用List<Integer>而不是List<int> ）。

这可能是两个最大的区别，但是从头开始学习Java泛型而不是C＃中的“差异”是非常值得的。

That's a pretty huge question, to be honest - the biggest differences aren't in syntax, but in behaviour... at which point they're really, really different.

I would suggest you read through the Sun generics tutorial and Angelika Langer's Java Generics FAQ. Forget everything you know about generics from C#/.NET first though. In particular, while .NET generic types retain the type argument at execution time, Java generics don't due to type erasure.

So in other words, in C# you can write:

public class GenericType<T> { public void DisplayType() { Console.WriteLine(typeof(T)); } }

... you can't do this in Java :(

Additionally, .NET generics can have value type type arguments, whereas Java generics can't (so you have to use List<Integer> instead of List<int> for example).

Those are probably the two biggest differences, but it's well worth trying to learn Java generics from scratch instead of as a "diff" from C#.