@Size(min, max) but not required

Question

Hi In my spring webapp I have a password variable which I want to be at least 0 characters or more than 6 and less than 20. I know that there is annotation:

 @Size(min=6, max=20)

but I have no idea how to add possibility that password can be 0 characters. Will somebody help me with this?

Answer 1

If you want a String which is either empty ("") or between 6 and 20 characters long, you could specify a regular expression using the @Pattern constraint:

@Pattern(regexp="(^$|.{6,20})")