What the output regular expression in Java matches to

The way to use Str.matches (REG) in Java is to return a Boolean value, and we sometimes need to return the content of the matching value, the implementation code is as follows:

 Public Static void Main (string[] args) {        = "2[0-9]{11}-{0,1}[0-9]{0,1}";         = Pattern.compile (reg);         = "200000000000-2200000000000";         =P.matcher (str);          while (M.find ())            System.out.println (M.group (0));                }

This will output all the matching content.

What the output regular expression in Java matches to