我正在使用 spring boot 編寫 OneToMany 關系，一個屬性可以有多個 propertySale。這是我的財產類別：@Data@Getter@Entity@Table(name = "Property")public class Property {    @Id    @GeneratedValue    private Long id;    @OneToMany(mappedBy="property", cascade = CascadeType.ALL, targetEntity = PropertySale.class)    @JsonManagedReference    private Set<PropertySale> propertySales;...這是我的 propertySale 類：@Data@Getter@Entity@Table(name = "PropertySale")public class PropertySale {    @Id    @GeneratedValue    private Long id;    @ManyToOne(fetch = FetchType.LAZY)    @JoinColumn(name = "property_id", referencedColumnName = "id")    @JsonBackReference    private Property property;...我像這樣保存 propertySale：@Override    public ResponseEntity<PropertySale> savePropertySale(PropertySale propertySale) {        Optional<Property> existPropertyOpt = this.propertyRepository.findById(propertySale.getProperty().getId());        if(existPropertyOpt.isPresent()){            Example<PropertySale> propertySaleExample =  Example.of(propertySale);            Optional<PropertySale> existPropSale = this.propertySaleRepository.findOne(propertySaleExample);            if(existPropSale.isPresent()){                throw new PropertySaleAlreadyExistException();            }else{                Property existProperty = existPropertyOpt.get();                propertySale.setProperty(existProperty);                existProperty.addPropertySale(propertySale);                this.propertyRepository.save(existProperty);                return new ResponseEntity<>(propertySale, HttpStatus.CREATED);            }        }else{            throw new PropertyNotFoundException(propertySale.getProperty().getId());        }    }當我嘗試保存房產銷售時，有人可以告訴我哪里做錯了嗎？非常感謝。