Remove all blank spaces at the beginning and end of a regular expression word

You can use the following regular expression to remove 'blanks' (spaces, tabs, ...) at the beginning and end of a string:

mensaje.replaceAll("^\p{Zs}+|\p{Zs}+$", "");

It seems that trim does not work because the text in question must be using one of the other alternative unicode spaces

With respect to the regular expression, the difference with respect to \s is that \s would only deal with the ASCII spaces, while \p{Zs} also takes the unicode spaces into account.

Another option could be to use StringUtils.strip , as discussed in this entry in StackOverflow. It seems that it would work with the different unicode spaces.

You may not be calling the trim function correctly, try it this way:

public class Task {

    public static void main(String[] args) {


        String source = "    4. numero de identificación    ";
        String result = source.trim();

        System.out.println(result);

    }

}

Documentation: trim function