How to extract region information from aws s3 virtual path uri using regex using java?

I need to extract region information from s3 virtual based path uri as follows.
https://<bucket_name>.s3.<region_name>.<domain>.com/

My intention is to fetch the region name from s3 uri and provide the region while creation s3client using aws java sdk 2.x.

Can anyone help me with the regex for this?

Try this:

public class RegexTest {
    public static void main(String[] args) {
        String url = "https://mybucket.s3.us-west-1.com/";

        Pattern p = Pattern.compile("https:\\/\\/.*\\.s3\\.(.*)\\.com");

        Matcher matcher = p.matcher(url);

        if(matcher.find()) {
            System.out.println(matcher.group(1));
        }
    }
}

matcher.group(0) will give you the entire match (the full URL in this case). Calling matcher.group(1) will get the first matched group, that is the first part of the regex encapsuled in ()