在我的默认页面上，我有一个隐藏的字段来设置托管细节。我已经检查了HTML源代码，值是空的。

• 我试图检查控制器本身是否正在发送null数据。但是，数据是由控制器按预期发送的。
• 我试着调试JSP，input标签正确地显示了相同的值，而Spring的form标签显示的值为空。
• 无BindingResult错误
  包含所有必需getter和setter的对象属性：

public class MakeSwitchForm implements Serializable {
    private Custody custody;
    private List<Custody> custodyList;

字符串

控制器

@GetMapping
public String defaultView(Model model, HttpServletRequest request, HttpServletResponse response, @RequestHeader(name = "Accept-Language") String locale)
        throws ServletException, IOException, PropertyValueNotFoundException, NoSuchMessageException  {
MakeSwitchForm form = new MakeSwitchForm();
List<Custody> custodyList = null;
custodyList = filterUserRightCustodies(redCustody, custodyList);// fetches custody list
form.setCustodyList(custodyList);
model.addAttribute("makeSwitchForm", form);

型

JSTL

<form:form id="makeSwitchForm" name="makeSwitchForm" modelAttribute="makeSwitchForm" action="${actionUrl}/makeSwitch" method="post" class="opux-g-container">
<%@ include file="subscriptionSection.jspf"%>

型

subscriptionSection.jspf

<c:choose>
     <c:when test="${fn:length(makeSwitchForm.custodyList) == 1}">
        <input type="hidden" value="<c:out value="${makeSwitchForm.custodyList[0].custodyNumber}" />" id="custodyNumber_0" />
         <form:hidden path="custody.custodyNumber" value="${makeSwitchForm.custodyList[0].custodyNumber}" />

型

HTML源代码

<input type="hidden" value="0007832348" id="custodyNumber_0">  
<input id="custody.custodyNumber" name="custody.custodyNumber" value="" type="hidden">

型
有人可以帮助我理解为什么<form:hidden>值设置为空吗？