Java Regex for telephone number - Must Include only 8 digits with not more than 2 dash

Question

I need your help with this one. I have to form a regex that accepts only 8 digits (no letters) with no or less than 3 dashes.

It should accept these examples:

12345678
1234 5678
1234-5678
123-45-678
12-345-678

It should not accept these examples:

1234 (less than 8 digits)
123456789 (more than 8 digits)
-12345678-
!@@#$%
12ABCBDEF (with letters)
12-34-56-78 (more than 3 dashes)

Any help is appreciated.

Answer 1

^(?=(?:\D*\d){8}$)\d+(?:(?:-\d+){0,2}|(?:\s+\d+){0,1})$

You can try this.See demo.

https://regex101.com/r/hE4jH0/20