Spring MVC不显示表单错误

Question

Here's my 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();
}

Here's the render library That I have created.

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;
    }
}

Here's my validator

Here's my form.

        <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>

On my controler the binding result has errors. however, the error is not being displayed on the view, what am I missing?

Answer 1

The problem is the way you are constructing your ModelAndView , you should use the Errors object to construct it. Use Errors.getModel() to obtain the underlying Map that represents the model and use that, next to the view name, to construct the ModelAndView .

Next to that for your other model attributes you should simply add @ModelAttribute annotated methods to retrieve those. I would also suggest adding a GET based method which you redirect to after successful submit.

Your helper class seems also rather pointless as doing it simply inside your controller would simplify your code (imho).

Your controller could look something along these lines.

@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());
}