"Mastering Jakarta Struts" is a decent book. Why are you after another one? Are you in search of more details, depth and advanced topics, or are you after another introductory explanation?
If "Mastering Jakarta Struts" explains things well enough for you, then perhaps the thing to do to learn Struts better is to just develop something new - not follow another set of examples - while referring back to "Mastering Jakarta Struts" and the internet as necessary.
I haven't read it yet, but I'll likely be reading the free copy of "Jakarta Struts Live" that
Pradeep Bhat mentioned is being given away.