java regex matching ip address and port number as captured groups

Answer 1

Unless you really, really have to do IP adress validation, as well, I suggest you simplify the regular expression, because this beast is far too complex for only matching "IP part" and "port part". My suggestion would be

(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}):(\d{1,5})

Groups 1 and 2 will hold IP and port, respectively. And the above is already more complex that it needs to be, IMHO even something as simple as this would be enough:

(\d+\.\d+\.\d+\.\d+):(\d+)

Note that double backslashes are are requirement of Java strings, not of regex, so I left them out.