I've added @Pattern annotation to a query parameter in my rest controller (SpringBoot Kotlin). I would like the regex in the pattern to accept -
optionA or optionB or null (nothing/an empty string)
The following works, but of course does not include the empty option -
@Pattern(regexp = "(?i)optionA||(?i)optionB")
This does not work -
@Pattern(regexp = "(?i)optionA||(?i)optionB||^\\s*\$")
Can anybody help me with this? :) Thanks!
I tryed this optionA|optionB|^\s$ on https://regex101.com/ and worked well. Could you try on your app to check?
Inside the @Pattern annotation, the pattern is used to match the entire string, so you can use
@Pattern(regexp = "(?i)(?:optionA)?")
which is actually \A(?i)(?:optionA)?\z:
\A - start of string (implicit here)(?i) - case insensitive embedded flag option(?:optionA)? - an optional non-capturing group that matches optionA or empty string\z - end of string (implicit here).The null is a memory address, not a string, it cannot be matched with regex, as regex only deals with strings.