您可以在地图值上指定泛型类型吗？

Question

In Java (5+) you can do:

TreeMap<String, List> map = someObject.getMap();

But can specify the generic type within the List ? A la:

TreeMap<String, List<String>> map = someObject.getMap();

??

Answer 1

You sure can. Works great.

Answer 2

Yes you can. Do you have a compiler error in your code you want help fixing?

Answer 3

Yes,why not? But keep in mind that the type gets erased in the compiled code, so isn't runtime available. That can be a problem if you access it with reflection.

Answer 4

You can nest generic types to arbitrary number of levels. Eg :

 TreeMap<String, List<Map<String, String>>>