feat: add exception handling

src/main/java/com/example/bankcards/exception/AccessDeniedException.java

@@ -0,0 +1,8 @@
+package com.example.bankcards.exception;
+
+public class AccessDeniedException extends RuntimeException {
+
+    public AccessDeniedException(String message) {
+        super(message);
+    }
+}

src/main/java/com/example/bankcards/exception/BadRequestException.java

@@ -0,0 +1,8 @@
+package com.example.bankcards.exception;
+
+public class BadRequestException extends RuntimeException {
+
+    public BadRequestException(String message) {
+        super(message);
+    }
+}

src/main/java/com/example/bankcards/exception/GlobalExceptionHandler.java

@@ -0,0 +1,66 @@
+package com.example.bankcards.exception;
+
+import com.example.bankcards.dto.ErrorResponse;
+import java.util.HashMap;
+import java.util.Map;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.FieldError;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(ResourceNotFoundException.class)
+    public ResponseEntity<ErrorResponse> handleNotFound(
+        ResourceNotFoundException ex
+    ) {
+        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(
+            new ErrorResponse(404, ex.getMessage())
+        );
+    }
+
+    @ExceptionHandler(BadRequestException.class)
+    public ResponseEntity<ErrorResponse> handleBadRequest(
+        BadRequestException ex
+    ) {
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(
+            new ErrorResponse(400, ex.getMessage())
+        );
+    }
+
+    @ExceptionHandler(AccessDeniedException.class)
+    public ResponseEntity<ErrorResponse> handleAccessDenied(
+        AccessDeniedException ex
+    ) {
+        return ResponseEntity.status(HttpStatus.FORBIDDEN).body(
+            new ErrorResponse(403, ex.getMessage())
+        );
+    }
+
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public ResponseEntity<ErrorResponse> handleValidation(
+        MethodArgumentNotValidException ex
+    ) {
+        Map<String, String> errors = new HashMap<>();
+        ex
+            .getBindingResult()
+            .getAllErrors()
+            .forEach(error -> {
+                String fieldName = ((FieldError) error).getField();
+                errors.put(fieldName, error.getDefaultMessage());
+            });
+        ErrorResponse response = new ErrorResponse(400, "Validation failed");
+        response.setErrors(errors);
+        return ResponseEntity.badRequest().body(response);
+    }
+
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<ErrorResponse> handleGeneral(Exception ex) {
+        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(
+            new ErrorResponse(500, "Internal server error: " + ex.getMessage())
+        );
+    }
+}

src/main/java/com/example/bankcards/exception/ResourceNotFoundException.java

@@ -0,0 +1,8 @@
+package com.example.bankcards.exception;
+
+public class ResourceNotFoundException extends RuntimeException {
+
+    public ResourceNotFoundException(String message) {
+        super(message);
+    }
+}