El Cato

@RestController
    public class ProductController {
        @PostMapping("/products")
        public ResponseEntity addProduct(@RequestBody Product product) {
            if (product.getPrice() < 0) {
                return ResponseEntity.status(HttpStatus.BAD_REQUEST).body("Price cannot be negative.");
            }
            repository.save(product);
            return ResponseEntity.status(HttpStatus.CREATED).body("Product added.");
        }
    }