使用 Thymeleaf + Mysql + Spring-boot 的动态级联下拉菜单

Question

帮助解决以下主题。

我正在使用 spring boot+thymeleaf+mysql+jpa

我有 2 个下拉列表，一个取决于另一个。 1.-“品牌”下拉菜单。 2.-下拉“产品”

我需要的帮助是，选择“品牌”下拉列表时，它会返回与所选品牌相关的产品。

你能帮我吗。 HTML

 <div class="col-md-3">
                        <label for="marcas" class="form-label col-form-label col-form-label-sm">* Marcas:</label>
                        <select class="form-select form-select-sm" id="marcas" required="">
                            <option value="0" selected>Selecionar...</option>
                            <option th:each="lista : ${listMarcas}"
                                    th:value="${lista.id}"
                                    th:text="${lista.marca}" th:href="@{/entradas/select/{valor}(valor=${lista.id})}">
                            </option>
                        </select>
                    </div>
                    <div class="col-md-3">
                        <label for="productos" class="form-label col-form-label col-form-label-sm">* Productos:</label>
                        <select class="form-select form-select-sm" id="productos" required="">
                            <option value="0" selected>Selecionar...</option>
                            <option th:each="lista : ${listProductos}"
                                    th:value="${lista.id}"
                                    th:text="${lista.producto}">
                            </option>
                        </select>
                    </div>

---

---

标题

Object 马卡

@Entity(name = "MarcaVo")

@Table(name = "CAT_MARCAS") public class MarcaVo 扩展 GenericoVo 实现 Serializable {

@Id
@Column(name = "ID")
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
@Column(name = "MARCA")
private String marca;

@OneToMany(mappedBy = "marcaVo", cascade = CascadeType.ALL, fetch = FetchType.LAZY, orphanRemoval = true)
@Fetch(FetchMode.SUBSELECT)
@LazyCollection(LazyCollectionOption.FALSE)
private List<ProductoVo> listProductoVo;

Object 产品展示

@Entity(name = "ProductoVo")

@Table(name = "CAT_PRODUCTOS") public class ProductoVo 扩展 GenericoVo 实现可序列化 {

@Id
@Column(name = "ID")
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
@Column(name = "PRODUCTO")
private String producto;
@Column(name = "ID_MARCA")
private int idMarca;
@Column(name = "ID_ANIMAL")
private int idAnimal;
@Column(name = "ID_PRESENTACION")
private int idPresentacion;

@ManyToOne()
@JoinColumn(name = "ID_MARCA", insertable = false, updatable = false)
@JsonIgnore
private MarcaVo marcaVo;

CONTROLLER

    @GetMapping("/entrada")
public String showEntrada(Model model) {
    model.addAttribute("entradaVo", new EntradaVo());
    model.addAttribute("listEntradas", entradaService.listAllEntradaVoByStatusFlag(true));
    model.addAttribute("listProveedores", proveedorService.listAllProveedorVoByStatusFlag(true));
    model.addAttribute("listMarcas", marcaService.listAllMarcaVoByStatusFlag(true));
    model.addAttribute("listAnimales", animalService.listAllAnimalVoByStatusFlag(true));
    model.addAttribute("listPresentaciones", presentacionService.listAllPresentacionVoByStatusFlag(true));
    //model.addAttribute("listProductos", productoService.listAllProductoVoByStatusFlag(true));
    model.addAttribute("listProductos", new ArrayList<ProductoVo>());
    model.addAttribute("fechaActual", DateUtils.dateToString());
    model.addAttribute("flag", true);
    return "pages/entrada";
}

干杯