Spring 注释@Validated 在 kotlin 类中不起作用，相同的 java 代码起作用

Question

I'm have kotlin get request. Validation are not working, Possible to specify day of week more or less validate limits

@RestController
@Validated
open class GetCrab {
    @GetMapping("/v1/get")
open fun getNameOfDayByNumber(@RequestParam dayOfWeek: @Min(1) @Max(7) Int?): String {
        return "ok"
    }
}

In the same java code validation works

@RestController
@Validated
public class GetCrab {

    @GetMapping("/v1/get")
    public String getNameOfDayByNumber(@RequestParam @Min(1) @Max(7) Integer dayOfWeek) {

        return "ok";
    }
}

Java code when validation works: request:

http://localhost:12722/v1/get?dayOfWeek=100

Response ->

{
"errors": [
    {
        "code": "INTERNAL_SERVER_ERROR",
        "details": "getNameOfDayByNumber.dayOfWeek: must be less than or equal to 7"
    }
]

}

Kotlin code, request http://localhost:12722/v1/get?dayOfWeek=100

Response:

ok

Answer 1

Please use open modifier for methods too.

Eg please try code:

@RestController
@Validated
open class GetCrab {
    @GetMapping("/v1/get")
    open fun getNameOfDayByNumber(@RequestParam dayOfWeek: @Min(1) @Max(7) Int?): String {
        return "ok"
    }
}

Both class and method should be open (in Java terms - both of them shouldn't be final), because of Spring proxy logic . From linked article: Spring tries to inherit your class, because sometimes you can request exact your class from @Autowired parameter.

By default all classes and methods are not final in Java . However Kotlin classes/methods are final by default , so you need to put open keyword before them to have ability to override.