如何用胸腺迭代并保存2个物体？

Question

我不知道解决此错误是如何解决的，我看到了一些有关此错误的文章，但没有任何作用。

错误

解决[org.springframework.validation.bindexception：org.springframework.validation.validation.validation.beanproperpertybindingresult：1 object'pupil'field'curse'curse'curse'curse'curse'curse'curse'curse'curse'curse'curse'curse'：deprodcurse'瞳孔= []，tocutlist = []）]; [无法将'java.lang.string'类型的属性值转换为必需的类型'com.example.administrator.administrator.model.model.model.modelcurse'用于属性'curse';

HTML

<form th:action="@{/pupilController/add}"  th:object="${pupil}" method="post">
            <div class="form-row">
                <div class="form-group col-md-6">
                    <label>Name</label>
                    <input type="text" class="form-control" th:field="*{name}" placeholder="Name">
                </div>
                <div class="form-group col-md-6">
                    <label>Last Name</label>
                    <input type="text" class="form-control" th:field="*{lastName}" placeholder="Last Name">
                </div>
                <div class="form-group col-md-6">
                    <label>Age</label>
                    <input type="number" class="form-control" th:field="*{age}" placeholder="Age">
                </div>
                <div class="form-group col-md-6">
                    <label>Phone Number</label>
                    <input type="text" class="form-control" th:field="*{phoneNumber}" placeholder="Phone Number">
                </div>
                <div class="form-group col-md-6">
                    <select th:field="*{curse}" class="form-control">
                        <option th:each="curso : ${curses}"
                                th:value="${curso}"
                                th:text="${curso.name}"></option>
                    </select>
                </div>
            </div>
    
            <input type="submit" name="btnInsert" class="btn btn-primary"  value=Añadir>
    
        </form>

控制器

 @GetMapping("/addPupil")
    public ModelAndView login(Model model){
        ModelAndView mav = new ModelAndView("addpupil");
        List<ModelCurse> modelCurses = curseService.getAllCurses();
        mav.addObject("pupil",new ModelPupil());
        mav.addObject("curses",modelCurses);
        return mav;
    }



 @PostMapping("/add")
    public RedirectView addPupil(@ModelAttribute("pupil")ModelPupil modelPupil){
        pupilService.addPupil(modelPupil);
        return new RedirectView("/pupilController/pupilList");
    }

DTO

@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class ModelCurse {

    private long id;
    private String name;
    private String division;
    private List<ModelPupil> pupilList;
    private List<ModelTeacher> teacherList;

}

@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class ModelPupil {

    private long id;
    private String name;
    private String lastName;
    private int age;
    private int phoneNumber;
    private ModelCurse curse;

}

Answer 1

当我们提交表单时，所选选项的值将以HTTP Post中的文本或字符串发送。因此，如果您期望Spring会自动将Curse的字符串值转换为类型modelscurse的对象，那么您的假设是错误的。
，但Spring确实为我们提供了一种使用Java Beans PropertyEditorSupport进行操作的方法。在这里，您可以扩展此类，并提供有关如何将该字符串转换为所需对象的实现。