+ in regualr expression
===

I am trying to capture a value out of a string. The string's format should be 

    01+XXXX

and I want to capture XXXX using a regular expression. This is what I came up with - 

    01+\\s*(?<1>[.0-9]*)

But that won't work. What DOES work is - 

    01+\\s*(?<1>[+.0-9]*)

The only difference is adding the + into the character class. My main question is - why does the second expression work and the first expression doesn't? In the first one, I look for 01+ and the rest of it should go to [.0-9]. It seems to me that the second one wants to read + twice - is that not what its doing? I am pretty new to regular expressions so I feel like I might be missing something small.

On this site http://www.codeproject.com/Articles/9099/The-30-Minute-Regex-Tutorial it says that + is used for "Repeat one or more times". So is it trying to read 01+ more than once? 