String manipulation using Java regexp

Question

I have a String in this format:

mydb://<user>:<password>@<host>:27017

And I would like to use Java regexp in order to extract the <user> and <password> strings from the String. What would be the best way doing so?

EDIT:

I would like to be able to use this regexp in the String's replace method so that I'm left only with the relevant user and password Strings

anubhava · Accepted Answer · 2025-03-15 09:34:16Z

7

You can use this regex (Pattern)

Pattern p = Pattern.compile("^mydb://([^:]+):([^@]+)@[^:]+:\\d+$");

And then capture group #1 and #2 will have your user and password respectively.

Code:

String str = "mydb://foo:bar@localhost:27017"; 
Pattern p = Pattern.compile("^mydb://([^:]+):([^@]+)@[^:]+:\\d+$");
Matcher matcher = p.matcher(str);
if (matcher.find())
    System.out.println("User: " + matcher.group(1) + ", Password: "
                        + matcher.group(2));

OUTPUT:

User: foo, Password: bar

RegEx Details:

^: Start
mydb://: Match mydb://
([^:]+): Match 1+ of any character other than : and capture in group #1
:: Match a :
([^@]+): Match 1+ of any character other than @ and capture in group #2
@: Match a @
[^:]+: Match 1+ of any character other than :
:: Match a :
\\d+: Match 1+ digits
$: End

EDIT: Based on your comments: if you want to use String methods then:

String regex = "^mydb://([^:]+):([^@]+)@[^:]+:\\d+$";
String user = str.replaceAll(regex, "$1");
String pass = str.replaceAll(regex, "$2")

edited Mar 15 at 9:34

answered Apr 20, 2012 at 20:52

anubhava

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3 Comments

Joly Over a year ago

thanks! Can I do this using one call to String replace method (see my EDIT above)?

anubhava Over a year ago

You'll need to call String#replaceAll twice for user and password separately.

Joly Over a year ago

I believe when using replace the regexp has to be changed a bit as we need to replace what we don't want with "" instead of extracting the user and the passwpord?

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