Java Spring表单在jsp上不起作用

我不熟悉spring框架。我试图在spring中使用MySQL jdbc制作简单的crud。对于数据映射，我使用了spring表单。每当我尝试使用spring form时，它都会显示一个错误

每当我删除spring表单并使用normalform时，它看起来还可以，但在使用spring表单时会显示一个错误。错误为java.lang.IllegalStateException：bean名称“userData”的BindingResult和普通目标对象都不能作为请求属性使用

header.jsp

谢谢大家!！希望得到好的回应

<form:form modelAttribute="userData">

   //rest of your form

</form:form>

请在index.jsp而不是当前版本中尝试此操作。

请尝试添加

  <%@include file="./shared/header.jsp" %>

<div class="container">
    <form:form commandName="userData" action="#" method="post" enctype="multipart/form-data">
        <label for="firstname" class="label">Enter your first name</label> 
        <form:input path="firstName"/>
    </form:form>
</div>

   @Controller

public class DefaultController {

    @Autowired
    CustomerDaoImp customerDaoImp;

    @RequestMapping(value = "/", method = RequestMethod.GET)
    public String index() {
        return "index";
    }

    @RequestMapping(value = "/insert", method = RequestMethod.POST)
    public String save(@ModelAttribute("userData") Customer customer) {
        try {
            customerDaoImp.insert(customer);
        } catch (ClassNotFoundException | SQLException ex) {
            System.out.println(ex.getMessage());
        }

        return "redirect:/index";
    }

    @RequestMapping(value = "/view", method = RequestMethod.GET)
    public String viewCustomer() {
        return "view-customer";
    }
}

<form:form modelAttribute="userData">

   //rest of your form

</form:form>