[英]@RequestParam is null (Spring MVC)
我正在尝试向Web应用程序添加编辑功能,但是使用@RequestParam
遇到了一些问题。 它获取的参数为null,不应为null。 我希望有人能指出我犯了一个错误。
这是控制器的方法:
@RequestMapping(value = "/edit", method = RequestMethod.GET)
public String getEdit(@RequestParam("customerId") Integer customerId, Model model) {
Customer existingCustomer = customerService.retrieveCustomer(customerId);
model.addAttribute("customerAttribute", existingCustomer);
return "edit-customer";
}
@RequestMapping(value = "/edit", method = RequestMethod.POST)
public String postEdit(@RequestParam("customerId") Integer customerId,
@ModelAttribute("customerAttribute") @Valid Customer customer, BindingResult result) {
if (result.hasErrors()) {
return "edit-customer";
}
customer.setCustomerId(customerId);
customerService.editCustomer(customer);
return "redirect:/test/customer/list";
和两个jsp页面
edit-customer.jsp :
<body>
<h1>Edit Existing Customer</h1>
<c:url var="saveUrl" value="/test/customer/edit?customerId=${customerAttribute.customerId}" />
<form:form modelAttribute="customerAttribute" method="POST" action="${saveUrl}">
<table>
<tr>
<td><form:label path="customerId">Customer Id:</form:label></td>
<td><form:input path="customerId" disabled="true"/></td>
</tr>
<tr>
<td><form:label path="customerCountry">Customer Country</form:label></td>
<td><form:input path="customerCountry"/></td>
</tr>
<tr>
<td><form:label path="customerName">Customer Name:</form:label></td>
<td><form:input path="customerName"/></td>
</tr>
</table>
<input type="submit" value="Save" />
</form:form>
</body>
view-all-customers.jsp :
<body>
<a href="<c:url value="/test/home"/>">Home</a>
<h1>Customers</h1>
<c:url var="addUrl" value="/test/customer/add" />
<c:url var="editUrl" value="/test/customer/edit?customerId=${customer.customerId}"/>
<c:if test="${!empty customers}">
<a href="${addUrl}">Add</a>
</c:if>
<table style="border: 1px solid; width: 500px; text-align:center">
<thead style="background:#ccc">
<tr>
<th>Customer Id</th>
<th>Customer Country</th>
<th>Customer Name</th>
<th colspan="4"></th>
</tr>
</thead>
<tbody>
<c:forEach items="${customers}" var="customer">
<tr>
<td><c:out value="${customer.customerId}" /></td>
<td><c:out value="${customer.customerCountry}" /></td>
<td><c:out value="${customer.customerName}" /></td>
<td><a href="${editUrl}">Edit</a></td>
</tr>
</c:forEach>
</tbody>
</table>
<c:if test="${empty customers}">
There are currently no customers in the list. <a href="${addUrl}">Add</a> a customers.
</c:if>
</body>
谁能看到为什么GET
方法中的Integer customerId
为null?
谢谢你D
在初始化之前,您正在使用${customer.customerId}
:
<!-- you use it here -->
<c:url var="editUrl" value="/test/customer/edit?customerId=${customer.customerId}"/>
<c:if test="${!empty customers}">
....
<tbody>
<!-- and initialize it here -->
<c:forEach items="${customers}" var="customer">
<tr>
<td><c:out value="${customer.customerId}" /></td>
<td><c:out value="${customer.customerCountry}" /></td>
<td><c:out value="${customer.customerName}" /></td>
<td><a href="${editUrl}">Edit</a></td>
</tr>
</c:forEach>
</tbody>
</table>
只需在循环内设置editUrl
:
<c:if test="${!empty customers}">
....
<tbody>
<c:forEach items="${customers}" var="customer">
<c:url var="editUrl" value="/test/customer/edit?customerId=${customer.customerId}"/>
<tr>
<td><c:out value="${customer.customerId}" /></td>
<td><c:out value="${customer.customerCountry}" /></td>
<td><c:out value="${customer.customerName}" /></td>
<td><a href="${editUrl}">Edit</a></td>
</tr>
</c:forEach>
</tbody>
</table>
它应该工作。 无论如何,您都必须为每个客户重置editUrl
。
可能是因为您将customerId接受为Integer,请尝试将其接受为String。 试试这个:
@RequestMapping(value = "/edit", method = RequestMethod.GET)
public String getEdit(@RequestParam("customerId") String customerId, Model model) {
Customer existingCustomer = customerService.retrieveCustomer(Integer.parseInt(customerId));
model.addAttribute("customerAttribute", existingCustomer);
return "edit-customer";
}
@RequestMapping(value = "/edit", method = RequestMethod.POST)
public String postEdit(@RequestParam("customerId") String customerId,
@ModelAttribute("customerAttribute") @Valid Customer customer, BindingResult result) {
if (result.hasErrors()) {
return "edit-customer";
}
customer.setCustomerId(Integer.parseInt(customerId));
customerService.editCustomer(customer);
return "redirect:/test/customer/list";
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