📝 docs: service layer design

README.md

@@ -1,5 +1,6 @@
 ## Docs
 
-- [docker-compose](docs/docker-compose.md)
-- [kubernetes](docs/kubernetes.md)
-- [package-structure](docs/package-structure.md)
+- [Package 구조](docs/package-structure.md)
+- [Service layer 개발 방법](docs/service.md)
+- [Docker Compose 사용 방법](docs/docker-compose.md)
+- [Kubernetes 사용 방법](docs/kubernetes.md)

docs/service.md

@@ -0,0 +1,27 @@
+## Exception Handling
+
+> Service layer의 exception handling은 [`GlobalExceptionHandler`](src/main/java/com/server/global/error/handler/GlobalExceptionHandler.java)를 통해 관리
+
+```java
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(AuthException.class)
+    public ResponseEntity<ApiResponseDto<Object>> handleFriendException(AuthException e) {
+        return ResponseEntity.status(e.getStatus()).body(ApiResponseDto.error(e.getStatus(), e.getMessage()));
+    }
+
+    @ExceptionHandler(BusinessException.class)
+    public ResponseEntity<ApiResponseDto<Object>> handleFriendException(BusinessException e) {
+        return ResponseEntity.status(e.getStatus()).body(ApiResponseDto.error(e.getStatus(), e.getMessage()));
+    }
+
+}
+```
+
+> [`ErrorCode`](src/main/java/com/server/global/error/code) 및 [`Exception`](src/main/java/com/server/global/error/exception) 정의 후 아래 예시와 같이 service layer에서 예외 생성
+
+```java
+throw new AuthException(AuthErrorCode.OAUTH_PROCESS_ERROR);
+throw new BusinessException(FriendErrorCode.RECEIPT_ALREADY_EXISTS);
+```