How to trim/cut string in java by symbol?

Question

I'm working on a project where my API returns url with id at the end of it and I want to extract it to be used in another function. Here's example url:

 String advertiserUrl = http://../../.../uuid/advertisers/4 <<< this is the ID i want to extract.

At the moment I'm using java's string function called substring() but this not the best approach as IDs could become 3 digit numbers and I would only get part of it. Heres my current approach:

String id = advertiserUrl.substring(advertiserUrl.length()-1,advertiserUrl.length());
System.out.println(id) //4

It works in this case but if id would be e.g "123" I would only get it as "3" after using substring, so my question is: is there a way to cut/trim string using dashes "/"? lets say theres 5 / in my current url so the string would get cut off after it detects fifth dash? Also any other sensible approach would be helpful too. Thanks.

P.s uuid in url may vary in length too

Answer 1

You don't need to use regular expressions for this.

Use String#lastIndexOf along with substring instead:

String advertiserUrl = "http://../../.../uuid/advertisers/4";// <<< this is the ID i want to extract.
// this implies your URLs always end with "/[some value of undefined length]". 
// Other formats might throw exception or yield unexpected results
System.out.println(advertiserUrl.substring(advertiserUrl.lastIndexOf("/") + 1));

Output

4

Update

To find the uuid value, you can use regular expressions:

String advertiserUrl = "http://111.111.11.111:1111/api/ppppp/2f5d1a31-878a-438b-a03b-e9f51076074a/adver‌​tisers/9";
//                           | preceded by "/"
//                           |     | any non-"/" character, reluctantly quantified
//                           |     |     | followed by "/advertisers"
Pattern p = Pattern.compile("(?<=/)[^/]+?(?=/adver‌​tisers)");
Matcher m = p.matcher(advertiserUrl);
if (m.find()) {
    System.out.println(m.group());
}

Output

2f5d1a31-878a-438b-a03b-e9f51076074a