CODEWITHSUNDEEP
javaregex
medium
medium

Reputation: 4236

regex multiple ip addresses from a string

I have a string which contains multiple ip addresses like so:

 String header = "Received: from example.google.com ([192.168.0.1]) by example.google.com ([192.168.0.2]) with mapi; Tue, 30 Nov 2010 15:26:16 -0600";

I want to use regular expression to get both IP's from this. I so far my code looks like this

public String parseIPFromHeader(String header) {
    Pattern p = Pattern.compile("\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b");
    Matcher m = p.matcher(header);
    boolean matchFound = m.find();

    System.out.println(matchFound);

    if (matchFound) {
         // Get all groups for this match
        for (int i=0; i<=m.groupCount(); i++) {
            // Get the group's captured text
            String groupStr = m.group(i);

            // Get the group's indices
            int groupStart = m.start(i);
            int groupEnd = m.end(i);

            // groupStr is equivalent to
            System.out.println(header.subSequence(groupStart, groupEnd));
        }
    }
}

but I never get match. Am I approaching this correctly? Thanks

Upvotes: 0

Views: 2806

Answers (2)

bongi
bongi

Reputation: 41

If you only need the IP adresses you can greatly simplify your regex to match just those

"([0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3})" //not perfect, i know...

And then use Matcher.find() multiple times to find all occurences in the string

while(m.find()) {
    String ip = m.group(1) //the first group is at index 1, group 0 is the whole match. (Does not actually make any difference here)
}

Upvotes: 0

Gabor Garami
Gabor Garami

Reputation: 1265

You escaped \ characters before dots, but if i remember correcly, you need escape it in \b sequence too, so replace them with \\b

Upvotes: 6

Related Questions