如何以更好的方式在控制器的视图中说出触发错误/验证消息？目前，我通过发送布尔属性来做到这一点。例如，在创建产品时，我有两个可能的错误。产品的UPC格式无效，或者复制upc。我也有一个有效的
@RequestMapping("/createProduct")
public String createProduct(Model model, @RequestParam(value = "name") String name,
@RequestParam(value = "upc") String upc, @RequestParam(value = "category") String categoryName,
@RequestParam(value = "description") String description, @RequestParam(value = "price") BigDecimal price,
@RequestParam(value = "stock") int stock){
model.addAttribute("activeTab", 3);
if(Validator.invalidUpcFormat(upc)){
model.addAttribute("invalidFormat", true); //trigger for invalid format
return "management";
}
Category category = productService.getCategory(categoryName);
Product product = new Product(upc, category, name, description, price);
InventoryProduct inventoryProduct = new InventoryProduct(product, stock);
try {
managerService.add(inventoryProduct);
model.addAttribute("productCreated", true);
} catch (DuplicateProductException e) {
model.addAttribute("upc", upc);
model.addAttribute("duplicateProduct", true); // trigger for duplicate product
}
return "management";
}
以下是我的观点：
<div id="menu3"
class="tab-pane fade <c:if test="${activeTab == 3}">in active</c:if>">
<div class="container-fluid" style="padding: 2%;">
<div class="row">
<div class="col-md-12"
style="padding-left: 15%; padding-right: 15%;">
<c:if test="${productCreated}">
<div class="alert alert-success fade in">
<a href="#" class="close" data-dismiss="alert"
aria-label="close">×</a> <strong>Success!</strong>
Product has been created!
</div>
</c:if>
<c:if test="${duplicateProduct}">
<div class="alert alert-warning fade in">
<a href="#" class="close" data-dismiss="alert"
aria-label="close">×</a> <strong>Oh no!</strong>
Product with the UPC ${upc} already exists!
</div>
</c:if>
<c:if test="${invalidFormat}">
<div class="alert alert-warning fade in">
<a href="#" class="close" data-dismiss="alert"
aria-label="close">×</a> <strong>Oops!</strong>
Invalid UPC format!
</div>
</c:if>
<form
action="${pageContext.request.contextPath}/manager/createProduct"
method="post">
<div class="form-group">
<label for="Name">Name </label> <input type="text" name="name"
class="form-control" required />
</div>
<div class="form-group">
<label for="UPC">UPC </label> <input type="number" name="upc"
class="form-control" required />
</div>
<div class="form-group">
<div class="form-group">
<label for="category">Category</label> <select
class="form-control" name="category" required>
<option selected disabled value="">SELECT CATEGORY</option>
<c:forEach items="${categories}" var="item">
<option>${item.getName()}</option>
</c:forEach>
</select>
</div>
</div>
<div class="form-group">
<label for="description">Description</label>
<textarea class="form-control" rows="5" name="description"></textarea>
</div>
<div class="form-group">
<label for="price">Price </label> <input type="number"
name="price" class="form-control" required />
</div>
<div class="form-group">
<label for="stock">Stock </label> <input type="number"
name="stock" class="form-control" required />
</div>
<button type="submit" class="btn btn-primary">Add
product</button>
</form>
</div>
</div>
</div>
</div>
除了发送布尔触发器之外，还有更好的做法吗？
答案 0 :(得分：2)
你可以使用Spring BindingResult。这通常填充了绑定和验证结果。但您也可以手动添加错误。
但首先您需要重构代码，以便使用单个命令/表单支持对象而不是所有@Param值
public class CreateProductCommand {
private String name;
private String upc;
private String categoryName;
.... //other fields
public CreateProductCommand (){} //parameter less conturctor
Getter+Setter
}
控制器
@RequestMapping("/createProduct")
public ModelAndView createProduct(CreateProductCommand createProductCommand, BindingResult bindingResult) //Binding result must be the parameter direct next to the object that should been validated!!!
{
if (someustomValidationForUcpFail()) {
bindingResult.rejectValue("upc", //the field name of the invalid field
"error.Message.Key",
"Default Error Message");
}
if (bindingResult.hasErrors()) {
ModelMap model = new ModelMap();
model.add("createProductCommand", createProductCommand);
return new ModelAndView("createForm", model)
} else {
Product product = ...
return new ModelAndView("showProduct", "product", product)
}
}
JSP：
您需要使用弹簧形式和输入标签：
<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page"
xmlns:c="http://java.sun.com/jsp/jstl/core"
xmlns:springForm="http://www.springframework.org/tags/form"
version="2.0">
....
<springForm:form action="<c:url value="/manager/createProduct">" method="POST" modelAttribute="createProductCommand">
<springForm:input path="name"/> <form:errors path="name" />
<springForm:input path="ucp"/> <form:errors path="ucp" />
....
</springForm:form>
....