Question

I have a text file, and loop though the file like this:

for ( int i = 0; i < this.textLines.size(); i++ ) {
    String tempString = textLines.get( i );

So now I have tempString containing something like:

46.102.241.199:3128 0.2990 Transp. NN N 100% 2011-11-19 17:56:02

What I want to to is return the IP:PORT part, in this case: 46.102.241.199:3128

How can I do that?

Answer 1

This regex would get you an IP with an optional port. If there’s always a port remove the questionmark at the end of the line.

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

Note that this is a simplified validation of an IPv4 and will only match that they are one the correct format and not a valid one. And remember to add an extra backslash to escape each backslash in java.

Here’s an example in java:

String text = "46.102.241.199:3128 0.2990 Transp. NN N 100% 2011-11-19 17:56:02";
String pattern = "\\d{1,3}(?:\\.\\d{1,3}){3}(?::\\d{1,5})?";

Pattern compiledPattern = Pattern.compile(pattern);
Matcher matcher = compiledPattern.matcher(text);
while (matcher.find()) {
    System.out.println(matcher.group());
}

Output:

46.102.241.199:3128