Практикум Spring Boot — Simple CRM — Этап 8 — `RestExceptionHandler`

package com.example.crm.config;

import com.example.crm.service.CustomerNotFoundException;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import java.util.LinkedHashMap;
import java.util.Map;
import java.util.stream.Collectors;

@RestControllerAdvice
public class RestExceptionHandler {

    @ExceptionHandler(CustomerNotFoundException.class)
    public ResponseEntity<Map<String, String>> handleNotFound(CustomerNotFoundException ex) {
        Map<String, String> body = Map.of("error", ex.getMessage());
        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(body);
    }

    @ExceptionHandler(MethodArgumentNotValidException.class)
    public ResponseEntity<Map<String, Object>> handleValidation(MethodArgumentNotValidException ex) {
        Map<String, String> errors = ex.getBindingResult().getFieldErrors().stream()
                .collect(Collectors.toMap(
                        error -> error.getField(),
                        error -> error.getDefaultMessage() != null ? error.getDefaultMessage() : "Invalid value",
                        (first, second) -> first,
                        LinkedHashMap::new
                ));

        Map<String, Object> body = new LinkedHashMap<>();
        body.put("error", "Validation failed");
        body.put("fields", errors);
        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(body);
    }
}