java - Spring MVC 不显示表单错误

Question

这是我的 Controller

@RequestMapping(value = "/save",method = RequestMethod.POST)
public ModelAndView saveUserAccount(@ModelAttribute("account") UserAccountForm userAccount, BindingResult result){
    AddUserValidator userValidator = new AddUserValidator();
    userValidator.validate(userAccount,result);
    boolean hasErrors = result.hasErrors();
    if(hasErrors){
        return render(ADD_USER_VIEW)
            .addAttr("ACCOUNT_ROLES", Arrays.asList(AccountRole.values()))
            .addAttr("TENANTS",tenantInfoService.getAll())
            .addAttr("errors",result)
            .addAttr("account",userAccount).toMav();
    }
    return render(ADD_USER_VIEW)
        .addAttr("ACCOUNT_ROLES", Arrays.asList(AccountRole.values()))
        .addAttr("TENANTS",tenantInfoService.getAll())
        .addAttr("account",new UserAccountForm())
        .toMav();
}

这是我创建的渲染库。

public class RenderMavBuilder {

    private final ModelAndView mav;

    public static RenderMavBuilder render(String viewname){
        RenderMavBuilder target = new RenderMavBuilder(viewname);
        return target;
    }

    public RenderMavBuilder addAttr(String attrName, Object value){
        mav.addObject(attrName, value);
        return this;
    }

    public RenderMavBuilder addAttr(Object value){
        mav.addObject(value);
        return this;
    }

    public RenderMavBuilder addAttrs(Map<String , ?> attrs){
        mav.addAllObjects(attrs);
        return this;
    }

    private RenderMavBuilder(String viewName){
        this.mav = new ModelAndView(viewName);
    }

    public ModelAndView toMav(){
        return mav;
    }
}

这是我的 validator

这是我的表格。

        <div class="col-md-6 centered">
            <form:errors path="*" />
            <form:form commandName="account" method="post" action="${pageContext.request.contextPath}/user/save">
                <!-- Username -->
                <div class="col-xs-12 form-group">
                    <label class="control-label">Username</label>
                    <form:input path="username" type="text" class="form-control" />
                </div>
                <!-- Password -->
                <div class="col-xs-12 form-group">
                    <label class="control-label">Password</label>
                    <form:password path="password" class="form-control"/>
                </div>


                <!-- Password -->
                <div class="col-xs-12 form-group">
                    <label class="control-label">Password</label>
                    <form:password path="retypedPassword"  class="form-control"/>
                </div>

                <!-- First Name -->
                <div class="col-xs-12 form-group">
                    <label class="control-label">First Name</label>
                    <form:input path="firstName" type="text" class="form-control"/>
                </div>

                <!-- First Name -->
                <div class="col-xs-12 form-group">
                    <label class="control-label">Last Name</label>
                    <form:input path="lastName" type="text" class="form-control"/>
                </div>

                <!-- User Role -->
                <div class="col-xs-12 form-group">
                    <label class="control-label">User Role</label>
                    <form:select path="accountRole" class="form-control">
                        <form:options items="${ACCOUNT_ROLES}"/>
                    </form:select>
                </div>

                <!-- Branch Designation -->
                <div class="col-xs-12 form-group">
                    <label class="control-label">Designated Branch</label>
                    <select path="tenantId" items="${TENANTS}" class="form-control">
                        <c:forEach var="branch" items="${TENANTS}">
                            <option value="${branch.id}">${branch.tenantDescription}</option>
                        </c:forEach>
                    </select>
                </div>
                <!-- Button -->
                <div class="col-md-12 form-group">
                    <button class="form-control btn btn-primary submit-button" type="submit">Save New User <i class="fa fa-check-square-o"></i></button>
                </div>
            </form:form>

在我的 Controller 上，绑定(bind)结果有错误。但是，错误没有显示在 View 上，我错过了什么？

Answer 1

问题在于您构建 ModelAndView 的方式，您应该使用 Errors 对象来构建它。使用 Errors.getModel() 获取表示模型的底层 Map，并在 View 名称旁边使用它来构造 ModelAndView 。

在其他模型属性旁边，您只需添加 @ModelAttribute 带注释的方法即可检索这些属性。我还建议添加一个基于 GET 的方法，您可以在成功提交后重定向到该方法。

您的帮助程序类似乎也毫无意义，因为仅在 Controller 内执行它会简化您的代码(恕我直言)。

你的 Controller 可能看起来像这样。

@RequestMapping(value = "/save",method = RequestMethod.POST)
public ModelAndView saveUserAccount(@ModelAttribute("account") UserAccountForm userAccount, BindingResult result){
    AddUserValidator userValidator = new AddUserValidator();
    userValidator.validate(userAccount,result);
    boolean hasErrors = result.hasErrors();
    return new ModelAndView(hasErrors ? ADD_USER_VIEW, "redirect:/add", errors.getModel());
}

@RequestMapping(value="/add")
public String addUserAccount(Model model) {
    model.addObject("account", new UserAccountForm());
    return ADD_USER_VIEW;
}

@ModelAttribute
public void referenceData(Model model) {
    model.addObject("ACCOUNT_ROLES", Arrays.asList(AccountRole.values()));
    model.addObject("TENANTS",tenantInfoService.getAll());
}