custom annotation on RequestParam and PathVariable

Question

I have created a custom annotation

annotation class UserControl(
    val userIdentifier: String
)

I wan to apply this annotation on query parameters, and path variables in different controllers.

    fun userWithMobile(
        @UserControl("PhoneNumber")
        @RequestParam mobile: String
    ): RegisteredUser {
        return userManager.getUserWithPhoneNumber(mobile))
    }

How can i check if the query parameters have the UserControl annotation or not, and do some processing on that. Is there standard way to write a global handler , or a processor for that?

Would appreciate any help

Answer 1

AspectJ can directly match parameter annotations, but not bind them to advice method values like class or method annotations. So if you only want to match them, a simple pointcut is enough. If you want to access the annotations and maybe their parameter values, you need a little bit of reflection magic. I have answered related questions many times already, which is why I am going to close this one as a duplicate. But first, here are the resources you want to read. They all related to your question, showing examples of how to handle different specific situations:

• https://stackoverflow.com/a/38162279/1082681
• https://stackoverflow.com/a/10595712/1082681
• https://stackoverflow.com/a/50540489/1082681
• https://stackoverflow.com/a/49872132/1082681
• https://stackoverflow.com/a/61284425/1082681
• https://stackoverflow.com/a/16624766/1082681

Basically, the pointcut you want the following or some variation of it:

execution(* *(.., @my.package.UserControl (*), ..))

The naive, less efficient approach without matching the parameter in the pointcut, using only relfection:

• https://stackoverflow.com/a/27784714/1082681
• https://stackoverflow.com/a/42561014/1082681