我的应用程序中有一个用于结账的简单控制器
一开始，我们将订单的对象转移到表单中：
@GetMapping
public String getOrderForm(Model model){
model.addAttribute("orderForm", new OrderDto());
model.addAttribute("deliveryType", orderService.getDeliveryTypeList());
model.addAttribute("paymentType", orderService.getPaymentTypeList());
return "create-order";
}
之后，用户在此对象中填写2个字段，所有字段都采用以下方法：
@PostMapping
public String addNewOrder(@ModelAttribute("orderForm") @Valid OrderDto orderDto,
@AuthenticationPrincipal UserDetails currentUser,
BindingResult bindingResult,
Model model,
RedirectAttributes redirectAttributes){
User userFromBd = userRepository.findByEmail(currentUser.getUsername());
orderDto.setUser_id(userFromBd.getId());
List<AddressDto> savedAddress = addressService.getAllSaved(orderDto.getUser_id());
model.addAttribute("savedAddress", savedAddress);
model.addAttribute("addressForm", new AddressAdditionDto());
return "order-address";
}
在这里，我们将其他对象传递到表单中，并让用户填写它们。这就是表单的样子：
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.w3.org/1999/xhtml">
<head>
<meta charset="UTF-8">
<title>Add new order</title>
</head>
<body>
<div th:each="address : ${savedAddress}">
<p>
<span th:text="*{address.country}"></span>
</p>
<p>
<span th:text="*{address.city}"></span>
</p>
</div>
<form th:method="POST" th:action="@{/order/savedaddress}">
<td>Choose adress:</td>
<select name="addressId">
<span th:each="address : ${savedAddress}">
<option th:value="${address.id}"
th:text="${address.id}"></option>
</span>
</select>
<br>
<label>
<input name="submit" type="submit" value="Select"/>
</label>
</form>
<p><a href="/">Home</a></p>
</body>
</html>
在这种形式中，不存在与原始OrderDTO对象的交互。此表单中的所有数据都采用以下方法：
@PostMapping("/savedaddress")
public String addAddress(@ModelAttribute("orderForm") @Valid OrderDto orderDto,
@RequestParam(value = "addressId", required = false) Long addressId,
BindingResult bindingResult,
Model model){
model.addAttribute("orderForm", orderDto);
if(orderDto.getPaymentType().equals("CARD")) {
model.addAttribute("savedCard", cardService.getAllByUserId(orderDto.getUser_id()));
model.addAttribute("cardForm", new CardRegisterDto());
return "order-card";
}
return "order-finish";
}
但问题是，我的OrderDTO对象已经完全空了。也就是说，在以前的表单中已经填写的字段是空的。它可以连接什么？
我认为您没有在HTML文件中使用OrderDto对象，这可能是将空对象作为ModelAttribute的原因。您可以在表单中使用th:object类似：
<form th:method="POST" th:action="@{/order/savedaddress}" th:object="${orderForm}">
<input type="hidden" th:field="*{user_id}">
'''
other code
'''
</form>
添加annotation@SessionAttributes(types={OrderDto.class}(高级
试试这个：
<form th:method="POST" th:action="@{/order/savedaddress} th:object={orderForm}">
<input type="hidden" th:value="${orderForm.user_id} name=userId">
<td>Choose adress:</td>
<select name="addressId">
<span th:each="address : ${savedAddress}">
<option th:value="${address.id}"
th:text="${address.id}"></option>
</span>
</select>
<br>
<label>
<input name="submit" type="submit" value="Select"/>
</label>
</form>