JPS useBean with HashMap

问题

How do I use jsp:useBean with collections like Lists and Maps correctly?

I can get Lists by using

    type="List<MyObject>"

but I cannot get the List to instantiate if nothing is passed.

    class="ArrayList<MyObject>"

And the above attribute gives an error:

The value for the useBean class attribute ArrayList<MyObject> is invalid.

And both the attributes fail for a HashMap.

Currently, I'm reading the objects using getAttribute() but it'll be cleaner to use the tags and set them up.

回答1:

Have you tried just

class="java.util.ArrayList"

Remember, the actual type name doesn't include the generic type, that's syntactic sugar used within the Java language itself, and <jsp:useBean> isn't part of the Java language.

来源：https://stackoverflow.com/questions/3263642/jps-usebean-with-hashmap