Question

I have an input string that will follow the pattern /user/<id>?name=<name>, where <id> is alphanumeric but must start with a letter, and <name> is a letter-only string that can have multiple spaces. Some examples of matches would be:

/user/ad?name=a a
/user/one111?name=one ONE oNe
/user/hello?name=world

I came up with the following regex:

String regex = "/user/[a-zA-Z]+\\w*\\?name=[a-zA-Z\\s]+";

All of the above examples match the regex, but it only looks at the first word in <name>. Shouldn’t the sequence \s allow me to have white spaces?

The code that I made to test what it is doing is:

String regex = "/user/[a-zA-Z]+\\w*\\?name=[a-zA-Z\\s]+";
// Check to see that input matches pattern
if(Pattern.matches(regex, str) == true){
   str = str.replaceFirst("/user/", "");
   str = str.replaceFirst("name=", "");
   String[] tokens = str.split("\\?");
   System.out.println("size = " + tokens.length);
   System.out.println("tokens[0] = " + tokens[0]);
   System.out.println("tokens[1] = " + tokens[1]);
} else
    System.out.println("Didn't match.");

So for example, one test might look like:

/user/myID123?name=firstName LastName
size = 2
tokens[0] = myID123
tokens[1] = firstName

whereas the desired output would be

tokens[1] = firstName LastName

How can I change my regex to do this?

Answer 1

Not sure what you think is the problem in your code. tokens[1] will indeed contain firstName LastName in your example.

Here’s an ideone.com demo showing this.

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However, have you considered using capturing groups for the id and the name.

If you write it like

String regex = "/user/(\\w+)\\?name=([a-zA-Z\\s]+)";

Matcher m = Pattern.compile(regex).matcher(input);

you can get hold of myID123 and firstName LastName through m.group(1) and m.group(2)