我正在使用 spring boot 编写 OneToMany 关系，一个属性可以有多个 propertySale。这是我的财产类别：@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;...这是我的 propertySale 类：@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;...我像这样保存 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());        }    }当我尝试保存房产销售时，有人可以告诉我哪里做错了吗？非常感谢。