How do I check if a text contains an IP address?

Question

I've searched around but have not found anything that works. How do I check if a text contains an IP address? I have tried this but it does not work:

    public boolean ip(String a_text) {
    String ip_filter = "\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}";
    if (a_text.toLowerCase().contains(ip_filter.toLowerCase())){
        return true;
    }
    return false;
}

possibly duplication of http://stackoverflow.com/questions/4581877/validating-ipv4-string-in-java — evgenyl, Mar 28 '13 at 18:58
@AndrewLogvinov, it's important to say that if OP uses `matches` than the regex needs to match with the whole String. Just as if it had begin/and anchors on the pattern. — Rodrigo Sasaki, Mar 28 '13 at 19:03
@RodrigoSasaki Yes, you're right. I didn't notice this. `Pattern` and `Matcher` seem more appropriate for this task, I think. — Andrew Logvinov, Mar 28 '13 at 19:08

Rodrigo Sasaki · Accepted Answer · 2013-03-28T19:09:29.583

You're trying to use a Regular Expression with the contains method. And that method does not receive a regex as argument. It receives a plain String. You should try using Pattern and Matcher.

Here's an example:

public static boolean ip(String text) {
    Pattern p = Pattern.compile("^(?:(?: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]?)$");
    Matcher m = p.matcher(text);
    return m.find();
}

EDIT: I updated the pattern to a more suitable one, found here.

score 1 · Answer 2 · edited Mar 28 '13 at 19:23

1

Yes, use match, and a better regular expression that I have used in the past is:

((0|1[0-9]{0,2}|2[0-9]?|2[0-4][0-9]|25[0-5]|[3-9][0-9]?)\.){3}(0|1[0-9]{0,2}|2[0-9]?|2[0-4][0-9]|25[0-5]|[3-9][0-9]?)

From RegExLib

edited Mar 28 '13 at 19:23

Mihai Bujanca

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answered Mar 28 '13 at 19:01

Bryan Hobbs

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score 0 · Answer 3 · edited May 23 '17 at 11:33

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You can do a lot of things with Regex. But Why should you!? You already have good and tested libraries, like Guava

boolean isValid = InetAddresses.isInetAddress("1.2.3.4");

Appache Validator

 isValidInet4Address(String)

And so on (see this post)

edited May 23 '17 at 11:33

Community

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answered Mar 28 '13 at 19:30

evgenyl

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How do I check if a text contains an IP address?

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