fix: issue130 Return a 404 error while adding a pet to an unexisting owner

src/main/java/org/springframework/samples/petclinic/rest/advice/ExceptionControllerAdvice.java

@@ -18,6 +18,7 @@
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
@@ -33,53 +34,76 @@
 import static org.springframework.http.HttpStatus.BAD_REQUEST;
 
 /**
+ * Global Exception handler for REST controllers.
+ * <p>
+ * This class handles exceptions thrown by REST controllers and returns
+ * appropriate HTTP responses to the client.
+ *
  * @author Vitaliy Fedoriv
+ * @author Alexander Dudkin
  */
-
 @ControllerAdvice
 public class ExceptionControllerAdvice {
 
-    @ExceptionHandler(Exception.class)
-    public ResponseEntity<String> exception(Exception e) {
-        ObjectMapper mapper = new ObjectMapper();
-        ErrorInfo errorInfo = new ErrorInfo(e);
-        String respJSONstring = "{}";
-        try {
-            respJSONstring = mapper.writeValueAsString(errorInfo);
-        } catch (JsonProcessingException e1) {
-            e1.printStackTrace();
+    /**
+     * Record for storing error information.
+     * <p>
+     * This record encapsulates the class name and message of the exception.
+     *
+     * @param className The name of the exception class
+     * @param exMessage The message of the exception
+     */
+    private record ErrorInfo(String className, String exMessage) {
+        public ErrorInfo(Exception ex) {
+            this(ex.getClass().getName(), ex.getLocalizedMessage());
         }
-        return ResponseEntity.badRequest().body(respJSONstring);
+    }
+
+    /**
+     * Handles all general exceptions by returning a 500 Internal Server Error status with error details.
+     *
+     * @param  e The exception to be handled
+     * @return A {@link ResponseEntity} containing the error information and a 500 Internal Server Error status
+     */
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<ErrorInfo> handleGeneralException(Exception e) {
+        ErrorInfo info = new ErrorInfo(e);
+        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(info);
+    }
+
+    /**
+     * Handles {@link DataIntegrityViolationException} which typically indicates database constraint violations.
+     * This method returns a 404 Not Found status if an entity does not exist.
+     *
+     * @param ex The {@link DataIntegrityViolationException} to be handled
+     * @return A {@link ResponseEntity} containing the error information and a 404 Not Found status
+     */
+    @ExceptionHandler(DataIntegrityViolationException.class)
+    @ResponseStatus(code = HttpStatus.NOT_FOUND)
+    @ResponseBody
+    public ResponseEntity<ErrorInfo> handleDataIntegrityViolationException(DataIntegrityViolationException ex) {
+        ErrorInfo errorInfo = new ErrorInfo(ex);
+        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(errorInfo);
     }
 
     /**
      * Handles exception thrown by Bean Validation on controller methods parameters
      *
      * @param ex      The thrown exception
-     * @param request the current web request
+     *
      * @return an empty response entity
      */
     @ExceptionHandler(MethodArgumentNotValidException.class)
-    @ResponseStatus(code = BAD_REQUEST)
+    @ResponseStatus(BAD_REQUEST)
     @ResponseBody
-    public ResponseEntity<Void> handleMethodArgumentNotValidException(MethodArgumentNotValidException ex, WebRequest request) {
+    public ResponseEntity<ErrorInfo> handleMethodArgumentNotValidException(MethodArgumentNotValidException ex) {
         BindingErrorsResponse errors = new BindingErrorsResponse();
         BindingResult bindingResult = ex.getBindingResult();
-        HttpHeaders headers = new HttpHeaders();
         if (bindingResult.hasErrors()) {
             errors.addAllErrors(bindingResult);
-            headers.add("errors", errors.toJSON());
+            return ResponseEntity.badRequest().body(new ErrorInfo("MethodArgumentNotValidException", "Validation failed"));
         }
-        return new ResponseEntity<>(headers, HttpStatus.BAD_REQUEST);
+        return ResponseEntity.badRequest().build();
     }
 
-    private class ErrorInfo {
-        public final String className;
-        public final String exMessage;
-
-        public ErrorInfo(Exception ex) {
-            this.className = ex.getClass().getName();
-            this.exMessage = ex.getLocalizedMessage();
-        }
-    }
 }

src/main/resources/openapi.yml

@@ -74,7 +74,7 @@ paths:
         required: true
       responses:
         201:
-          description: The pet owner was sucessfully added.
+          description: The pet owner was successfully added.
           content:
             application/json:
               schema:
@@ -314,7 +314,7 @@ paths:
         required: true
       responses:
         201:
-          description: The pet was sucessfully added.
+          description: The pet was successfully added.
           content:
             application/json:
               schema:
@@ -326,7 +326,7 @@ paths:
               schema:
                 $ref: '#/components/schemas/RestError'
         404:
-          description: Pet not found.
+          description: Pet or Owner not found.
           content:
             application/json:
               schema:
@@ -489,7 +489,7 @@ paths:
         required: true
       responses:
         201:
-          description: The vet visit was sucessfully added.
+          description: The vet visit was successfully added.
           content:
             application/json:
               schema:
@@ -1849,7 +1849,7 @@ components:
           readOnly: true
         timestamp:
           title: Timestamp
-          description: The time the error occured.
+          description: The time the error occurred.
           type: string
           format: date-time
           example: '2019-08-21T21:41:46.158+0000'
@@ -1886,7 +1886,7 @@ components:
       properties:
         message:
           title: Message
-          description: The valiation message.
+          description: The validation message.
           type: string
           example: "[Path '/lastName'] Instance type (null) does not match any allowed primitive type (allowed: [\"string\"])"
           readOnly: true

src/test/java/org/springframework/samples/petclinic/rest/controller/PetRestControllerTests.java

@@ -241,7 +241,8 @@ void testAddPetError() throws Exception {
         String newPetAsJSON = mapper.writeValueAsString(newPet);
         given(this.clinicService.findPetById(999)).willReturn(null);
         this.mockMvc.perform(post("/api/pets")
-                .content(new String()).accept(MediaType.APPLICATION_JSON_VALUE).contentType(MediaType.APPLICATION_JSON_VALUE))
+                // set empty JSON to force 400 error
+                .content("{}").accept(MediaType.APPLICATION_JSON_VALUE).contentType(MediaType.APPLICATION_JSON_VALUE))
             .andExpect(status().isBadRequest());
     }
 }

src/test/java/org/springframework/samples/petclinic/rest/controller/UserRestControllerTests.java

@@ -63,7 +63,7 @@ void testCreateUserSuccess() throws Exception {
     @WithMockUser(roles = "ADMIN")
     void testCreateUserError() throws Exception {
         User user = new User();
-        user.setUsername("username");
+        user.setUsername(""); // set empty username to force 400 error
         user.setPassword("password");
         user.setEnabled(true);
         ObjectMapper mapper = new ObjectMapper();