What is the best way to structure exception handling in a project containing multiple REST controllers, each of which provides CRUD operations for different entities?

The best way to structure exception handling in a project with multiple REST controllers is to use a centralized exception handler. In Spring Boot, for example, this is done using the @ControllerAdvice annotation, which allows creating a class that handles exceptions thrown from any controllers.

Advantages of this approach:

• A single place for error handling and forming responses to the client.
• Simplifies controller code — they do not need to handle exceptions locally.
• Easy to maintain and extend error handling.

Example:

@ControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(EntityNotFoundException.class)
    public ResponseEntity<String> handleNotFound(EntityNotFoundException ex) {
        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(ex.getMessage());
    }

    @ExceptionHandler(Exception.class)
    public ResponseEntity<String> handleGeneric(Exception ex) {
        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("Internal server error");
    }
}

Thus, all controllers can throw exceptions, and @ControllerAdvice will catch them and generate correct HTTP responses.