Extract ip addresses from Strings using regex

Question

In an application, I get strings containing IP Addresses but these string have no precise format. All we know is that these strings may contain an IP address.

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Answer 1

Richard's link helped me find the answer. here's the working code :

String IPADDRESS_PATTERN = 
        "(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)";

Pattern pattern = Pattern.compile(IPADDRESS_PATTERN);
Matcher matcher = pattern.matcher(ipString);
if (matcher.find()) {
    return matcher.group();
} else{
    return "0.0.0.0";
}