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I'm validating a form using the Validator interface with Spring MVC 3.0.2 using SimpleFormController. The following is the controller class which extends SimpleFormController.

@SuppressWarnings("deprecation")
final public class Temp extends SimpleFormController
{        
    public Temp()
    {
        setCommandClass(ValidationForm.class);
        setCommandName("validationForm");
    }

    @Override
    protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception
    {
        ValidationBean validationBean=(ValidationBean) command;
        ModelAndView mv=new ModelAndView("Temp", "validationForm", validationBean);
        if(errors.hasErrors())
        {
            System.out.println("error");
        }
        else
        {
            System.out.println("name = "+validationBean.getUserName());
        }
        return mv;
    }        

    @Override
    protected ModelAndView showForm(HttpServletRequest request, HttpServletResponse response, BindException errors) throws Exception
    {
        ModelAndView mv=new ModelAndView("Temp", "validationForm", errors.getTarget());
        return mv;
    }
}

There is no question about form-validation. It works fine. The only question here is that when I use the showForm(...){...} method as shown above, the error messages are not displayed because this method calls when the JSP page is loaded and also, after the onSubmit() method completes (In case, the page is submitted by clicking the submit button on the JSP page).

When the page is submitted by clicking the submit button, the command object which is errors.getTarget() (or getCommand(request)) in the showForm() method (which is called after the onSubmit() method) contains no error messages to be displayed on the page. The command object (or domain object) is different from the command object in the onSubmit() method. (and therefore, when the showForm() method is commented out, it displays error messages)

I need to use the showForm() method to display a list of data from the database when the page is either submitted or loaded.

Of course, the referenceData() method as shown below does the trick.

protected Map referenceData(HttpServletRequest request, Object command, Errors errors) throws Exception
{    
    Map map=new HashMap();
    return map;
}

but I want to stick at the showForm() method. Is there a fair way to display error messages while using the showForm() method while validating a form?

4

1 回答 1

1

在您的客户端，您可以使用错误对象的内容以及表单来显示错误。请注意 onSubmit() 和 showForm() 在 spring 3.0 中已弃用。

@SuppressWarnings("deprecation") 
final public class Temp extends SimpleFormController 
{         
    public Temp() 
    { 
        setCommandClass(ValidationForm.class); 
        setCommandName("validationForm"); 
    } 

    @Override 
    protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception 
    { 
        ValidationBean validationBean=(ValidationBean) command; 
        ModelAndView mv=new ModelAndView("Temp", "validationForm", validationBean); 
        if(errors.hasErrors()) 
        { 
            System.out.println("error"); 
            errors.reject("error.server.error");
            return showForm(request, response, errors);
        } 
        else 
        { 
            System.out.println("name = "+validationBean.getUserName()); 
        } 
        return mv; 
    }         

    @Override 
    protected ModelAndView showForm(HttpServletRequest request, HttpServletResponse response, BindException errors) throws Exception 
    { 
        ModelAndView mv=new ModelAndView("Temp", "validationForm", errors.getTarget()); 
        return mv; 
    } 
}

示例 JSP 代码：

例如在 jsp 中，如果您需要显示错误消息，您可以使用如下：

<span class="error">${error}</span>

error 是我们需要在 spring 中设置的属性。

于 2012-07-02T02:57:18.520 回答