How I can return my custom json file instead of default json file that generates spring boot? - spring

Question

I have a rest controller for authorization:
#RestController
class AuthController {
#PostMapping("/sign-up")
fun signUp(#RequestBody signUpRequest: SignUpRequest): ResponseEntity<String> {
some code here..
}
}
The signUp method gets SignUpRequest model as a request body. SignUpRequest model is:
enum class Role {
#JsonProperty("Student")
STUDENT,
#JsonProperty("Tutor")
TUTOR
}
data class SignUpRequest(
val role: Role,
val email: String,
val password: String
)
When I make /sign-up post request with JSON:
{
"role": "asdf",
"email": "",
"password": ""
}
It returns me an answer that were generated by spring boot:
{
"timestamp": "2020-02-12T05:45:42.387+0000",
"status": 400,
"error": "Bad Request",
"message": "JSON parse error: Cannot deserialize value of type `foo.bar.xyz.model.Role` from String \"asdf\": not one of the values accepted for Enum class: [Student, Tutor]; nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `foo.bar.xyz.model.Role` from String \"asdf\": not one of the values accepted for Enum class: [Student, Tutor]\n at [Source: (PushbackInputStream); line: 3, column: 10] (through reference chain: foo.bar.xyz.model.SignUpRequest[\"role\"])",
"path": "/sign-up"
}
Question is: How I can return my custom JSON instead of that default generated JSON?
I want to return my custom JSON, like:
{
"result": "Invalid user data are given",
"errors": [
{
"fieldName": "ROLE",
"text": "Given role does not exist"
},
{
"fieldName": "EMAIL",
"text": "EMAIL is empty"
}
]
}

Answer 1

I suggest you to create ErrorContrller that generates custom json map as response. Then when you will catch an error in sign-up method, call ErrorContrllers method.
You can find info from this link

Answer 2

Finally I found out a solution. You should create a class that annotates #ControllerAdvice, and make a method that annotates #ExceptionHandler.
#ControllerAdvice
class HttpMessageNotReadableExceptionController {
#ExceptionHandler(HttpMessageNotReadableException::class)
#ResponseBody
#ResponseStatus(HttpStatus.BAD_REQUEST)
fun handleException(
exception: HttpMessageNotReadableException
): PostSignUpResponseError {
val errors = mutableListOf<PostSignUpResponseErrorItem>()
errors.add(
PostSignUpResponseErrorItem(
fieldNamePost = "Role",
text = "Given role does not exist"
)
)
return PostSignUpResponseError(
result = "Invalid user data are given",
errors = errors
)
}
}
where PostSignUpResponseErrorItem and PostSignUpResponseError are:
data class PostSignUpResponseError(
val result: String,
val errors: List<PostSignUpResponseErrorItem>
)
class PostSignUpResponseErrorItem(
val fieldNamePost: PostSignUpRequestFieldName,
val text: String
)
Anyway, I still don't know how to attach this thing to a certain PostMapping method.