Thymeleaf：从表单

Question

假设我有一个实体：

@Entity
@Table(name = "Building")
@Data
public class Building {

@Id
@Column(name = "buildingId")
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer buildingId;

@OneToOne(cascade = {CascadeType.MERGE}
@JoinColumn(name = "buildingType")
private BuildingType buildingType;
 //...

}

在我的控制器中，我将所有建筑物类型都放入了模型：

@RequestMapping("/addBuilding")
    public String newBuilding(Model model, @ModelAttribute Building building){
       model.addAttribute("buildingTypes", buildingTypeService.getBuildingTypes()); //gives me an ArrayList<BuildingType>
}

现在我要遍历建筑物类型以将其放入下拉<select>：

<form class="some-form" method="post" th:action="@{/addBuilding}">
    <select id="type" class="some-class" required>
        <option th:each="buildingType : ${buildingTypes}" th:text="${buildingType.name}"></option>
    </select>
    <button type="submit" class="button">Store</butto>
</form>

这很好。但是，当我尝试获取所选的建筑物类型时：

<form class="some-form" method="post" th:action="@{/addBuilding}" th:object="${building}">
        <select id="type" class="some-class" th:field="*{buildingType}" required>
            <option th:each="buildingType : ${buildingTypes}" th:value="${buildingType}" th:text="${buildingType.name}"></option>
        </select>
        <button type="submit" class="button">Store</button>
</form>

我的控制器没有收到对象，而是一个字符串：

@RequestMapping("/addBuilding")
        public String newBuilding(Model model, @ModelAttribute Building building){
           //...
           System.out.println((building.getBuildingType() instanceof BuildingType)); //false
    }

是否可以从Thymeleaf获取对象？还是有必要为BuildingType创建一个原始的瞬态字段（例如String），从Thymeleaf返回它，并基于该字段在控制器中搜索BuildingType？