#PathVariable Validation in Spring 4 - spring

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
public class MyController {
#RequestMapping(value = "/{id}", method = RequestMethod.PUT)
public ResponseEntity method_name(#PathVariable String id) {
/// Some code
}
}
I tried doing adding validation to the path variable but its still not working
#RestController
#Validated
public class MyController {
#RequestMapping(value = "/{id}", method = RequestMethod.PUT)
public ResponseEntity method_name(
#Valid
#Nonnull
#Size(max = 2, min = 1, message = "name should have between 1 and 10 characters")
#PathVariable String id) {
/// Some code
}
}

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)
);
}