Spring ControllerAdvice global exception handler not returning response - spring

Question

I have a Groovy Spring Boot microservice that returns a list of posts. Requests come into the controller, the controller invokes a method in a service class, and if no posts are found, a custom error message is thrown.
I've created a controller annotated with #ControllerAdvice that I want to intercept errors, and a handler specific to the custom error. It should return a POJO. At present the ControllerAdvice handler is being invoked, but the response from the microservice is a 500 error
The controller
#RequestMapping(value ='getCommentList', method = RequestMethod.POST)
def getCommentList(#RequestBody requestParams) {
def response
String userId = requestParams.userId
String uuid = requestParams.uuid
response = commentService.findCommentsByUserIdAndUuid(userId, uuid)
}
The service method
def findCommentsByUserIdAndUuid(String userId, String uuid) {
User user = userRepository.findByUserId(userId)
Long userId = tenant?.id
List responses = commentRepository.findCommentsByUserAndUuidNotDeleted(userId, uuid)
if (responses.size() == 0) {
throw new CommentsNotFoundException()
} else {
def data = JsonOutput.toJson(retMap)
return data
}
}
the custom exception class
package com.news.exception
class CommentsNotFoundException extends Exception {
String errorMessage
def dataReturned
public commentsNotFoundException() {
NewsFeedMessage.buildRequestErrorMessageWithData(errorMessage, dataReturned)
}
}
The POGO to be returned
package com.news.utils
import org.springframework.http.HttpStatus
class NewsFeedMessage {
int httpStatus
String type
String message
def dataReturned
def subMessages = []
static NewsFeedMessage buildRequestErrorMessageWithData(mainMessage, data) {
return new NewsFeedMessage(
httpStatus: 400,
message: mainMessage,
dataReturned: data
)
}
}
And the global exception handler with#ControllerAdvice annotation
package com.news.exception
import com.newa.utils.NewsFeedMessage
import org.springframework.boot.configurationprocessor.json.JSON
import org.springframework.http.ResponseEntity
import org.springframework.web.bind.annotation.ControllerAdvice
import org.springframework.web.bind.annotation.ExceptionHandler
import org.springframework.web.context.request.WebRequest
import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler
#ControllerAdvice
public class GlobalExceptionHandler extends ResponseEntityExceptionHandler {
#ExceptionHandler(CommentsNotFoundException.class)
public NewsFeedMessage handleException() {
def response = NewsFeedMessage.buildRequestErrorMessageWithData("testing 1234", [])
//return response as JSON
}
}
When debugging, The code gets as far as
def response = NewsFeedMessage.buildRequestErrorMessageWithData("testing 1234", [])
However nothing is returned.
The returned message using Postman is:
{
"timestamp": "2020-10-23T16:27:35.572+0000",
"status": 500,
"error": "Internal Server Error",
"message": "No message available",
"path": "/comment/getCommentList"
}
Is there anything here that is glaringly wrong?

Answer 1

I think NewsFeedMessage is not supported return type. Check ExceptionHandler docs and there is a block about supported return types. Try returning a ResponseEntity<>(new NewsFeedMessage()).