@PathVariable Validation in Spring 4

Question

How can i validate my path variable in spring. I want to validate id field, since its only single field i do not want to move to a Pojo

@RestController
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Answer 1

You need to create a bean in your Spring configuration:

 @Bean
    public MethodValidationPostProcessor methodValidationPostProcessor() {
         return new MethodValidationPostProcessor();
    }

You should leave the @Validated annotation on your controller.

And you need an Exceptionhandler in your MyController class to handle theConstraintViolationException :

@ExceptionHandler(value = { ConstraintViolationException.class })
    @ResponseStatus(value = HttpStatus.BAD_REQUEST)
    public String handleResourceNotFoundException(ConstraintViolationException e) {
         Set<ConstraintViolation<?>> violations = e.getConstraintViolations();
         StringBuilder strBuilder = new StringBuilder();
         for (ConstraintViolation<?> violation : violations ) {
              strBuilder.append(violation.getMessage() + "\n");
         }
         return strBuilder.toString();
    }

After those changes you should see your message when the validation hits.

P.S.: I just tried it with your @Size validation.

Answer 2

To archive this goal I have apply this workaround for getting a response message equals to a real Validator:

@GetMapping("/check/email/{email:" + Constants.LOGIN_REGEX + "}")
@Timed
public ResponseEntity isValidEmail(@Email @PathVariable(value = "email") String email) {
    return userService.getUserByEmail(email).map(user -> {
        Problem problem = Problem.builder()
            .withType(ErrorConstants.CONSTRAINT_VIOLATION_TYPE)
            .withTitle("Method argument not valid")
            .withStatus(Status.BAD_REQUEST)
            .with("message", ErrorConstants.ERR_VALIDATION)
            .with("fieldErrors", Arrays.asList(new FieldErrorVM("", "isValidEmail.email", "not unique")))
            .build();
        return new ResponseEntity(problem, HttpStatus.BAD_REQUEST);
    }).orElse(
        new ResponseEntity(new UtilsValidatorResponse(EMAIL_VALIDA), HttpStatus.OK)
    );
}