Implements Hunt basic create and get, and adds field validation to controllers

src/main/kotlin/net/halfbinary/scavengerhuntapi/error/ExceptionHandler.kt

@@ -2,12 +2,17 @@ package net.halfbinary.scavengerhuntapi.error
 
 import net.halfbinary.scavengerhuntapi.error.exception.InvalidEmailException
 import net.halfbinary.scavengerhuntapi.error.exception.LoginFailedException
+import net.halfbinary.scavengerhuntapi.error.exception.NotFoundException
 import net.halfbinary.scavengerhuntapi.error.exception.PreexistingAccountException
 import org.springframework.http.HttpStatus
+import org.springframework.http.converter.HttpMessageNotReadableException
+import org.springframework.validation.FieldError
+import org.springframework.web.bind.MethodArgumentNotValidException
 import org.springframework.web.bind.annotation.ExceptionHandler
 import org.springframework.web.bind.annotation.ResponseStatus
 import org.springframework.web.bind.annotation.RestControllerAdvice
 
+
 @RestControllerAdvice
 class ExceptionHandler {
 
@@ -28,4 +33,27 @@ class ExceptionHandler {
     fun invalidEmailException(e: InvalidEmailException): String? {
         return e.message
     }
+
+    @ExceptionHandler(NotFoundException::class)
+    @ResponseStatus(HttpStatus.NOT_FOUND)
+    fun notFoundException(e: NotFoundException): String? {
+        return e.message
+    }
+
+    @ExceptionHandler(HttpMessageNotReadableException::class)
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    fun httpMessageNotReadableException(e: HttpMessageNotReadableException): String? {
+        return e.message
+    }
+
+    @ExceptionHandler(MethodArgumentNotValidException::class)
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    fun handleValidationExceptions(e: MethodArgumentNotValidException): Map<String, String?> {
+        return e.bindingResult.allErrors.associate { error ->
+            Pair(
+                (error as FieldError).field,
+                error.defaultMessage
+            )
+        }
+    }
 }