CODEWITHSUNDEEP
javaregex
Lolly
Lolly

Reputation: 36432

Regex to find hostname from Jdbc url

I am new to regex. I would like to retrieve the Hostname from postgreSQL jdbc URL using regex.

Assume the postgreSQL url will be jdbc:postgresql://production:5432/dbname. I need to retrieve "production", which is the hostname. I want to try with regex and not with Java split function. I tried with

Pattern PortFinderPattern = Pattern.compile("[//](.*):*");
final Matcher match = PortFinderPattern.matcher(url);
if (match.find()) {
    System.out.println(match.group(1));
}

But it's matching all the string from hostname till the end.

Upvotes: 2

Views: 5482

Answers (5)

FelixD
FelixD

Reputation: 639

To capture also Oracle and MySQL JDBC URL variants with their quirks (e.g. Oracle allowing to use @ instead of // or even @//), I use this regexp to get the hostname: [/@]+([^:/@]+)([:/]+|$) Then the hostname is in group 1.

Code e.g.

String jdbcURL = "jdbc:oracle:thin:@//hostname:1521/service.domain.local";
Pattern hostFinderPattern = Pattern.compile("[/@]+([^:/@]+)([:/]+|$)");
final Matcher match = hostFinderPattern.matcher(jdbcURL);
if (match.find()) {
  System.out.println(match.group(1));
}

This works for all these URLs (and other variants):

jdbc:oracle:thin:@//hostname:1521/service.domain.local
jdbc:oracle:thin:@hostname:1521/service.domain.local
jdbc:oracle:thin:@hostname/service.domain.local
jdbc:mysql://localhost:3306/sakila?profileSQL=true
jdbc:postgresql://production:5432/dbname
jdbc:postgresql://production/
jdbc:postgresql://production

This assumes that

  • The hostname is after // or @ or a combination thereof (single / would also work, but I don't think JDBC allows that).

  • After the hostname either : or / or the end of the string follows.

Note that the the + are greedy, this is especially important for the middle one.

Upvotes: 0

Lajos Mészáros
Lajos Mészáros

Reputation: 3866

There are some errors in your regex:

[//] - This is only one character, because the [] marks a character class, so it will not fully match //. To match it, you need to write it like this: [/][/] or \/\/.

(.*) - This will match all characters to the end of line. You need to be more specific if you want to go till a certain character. For example you could go to the colon by fetching all characters, which are not colons, like this: ([^:]*).

:* - This makes the colon optional. I guess you forgot to put a dot( every character ) after the colon, like this: :.*.

So here is your regex corrected: \/\/([^:]*):.*.

Hope this helps.

BTW. If the port number is optional after production (:5432), then I suggest the following regex: \/\/([^/]*)(?::\d+)?\/

Upvotes: 0

Kent
Kent

Reputation: 195229

regex without grouping :

"(?<=//)[^:]*"

Upvotes: 1

Mike Thomsen
Mike Thomsen

Reputation: 37526

[//]([\\w\\d\\-\\.]+)\:

Should be enough to find it reliably. Though this is probably a better regex:

The Hostname Regex

Upvotes: 0

ty733420
ty733420

Reputation: 894

Pattern PortFinderPattern = Pattern.compile(".*:\/\/([^:]+).*");

Upvotes: 1

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