validate struts2 form other than validation framework

Question

In my Struts2 JSP form, there are text fields and a select tag. For example,

<s:form>
<s:textfield name="name" label="Name"/>
<s:textfield name="dob" label="Date of Birth"/>
<s:select name="degree" list="degreeList" listKey="degreeID" listValue="degreeName"/>
<s:submit/>
</s:form>

Before this JSP is loaded, I filled degreeList in action class. I need to validate this form. So I tried the validation framework. But the problem is action class return "input" itself if the validation failed. I cannot refill the degreeList if the validation failed. So the above JSP cannot be loaded. The error says degreeList is not list/collection as the list is no longer in the value stack. Somebody please kindly guide me how can I validate in another way? Thanks.

This is what Prepareable is for. – Dave Newton Apr 28 '13 at 19:21 — Dave Newton, Apr 28 '13 at 19:21

Quaternion · Answer 1 · 2013-04-28T18:32:29.787

3

Nothing is stopping you from doing validation in execute() and returning what ever result string you wish, or throwing an exception.

But the real issue seems to be "I cannot refill the degreeList if the validation failed", why not, why can't you just send them back to the same form?

You should be able to annotate your action (or use struts.xml) to redirect to the appropriate page should "input" be returned, even if that means a page prior to the form being sent or less reasonably a page stating "sorry you put in the wrong values and because of the time sensitive nature of the form we can never give you the option of trying again :)"

Update:

@Results({ @Result(name="input", location="/package/my-action") })

edited Apr 28 '13 at 18:32

answered Apr 28 '13 at 18:01

Quaternion

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<> If I manually return "input" from action class method, yes I can refill the list in this method. But validation framework return "input" itself. As result "input" must go back to the form page to show error, but the list is not filled, the form page can't be shown. In order to refill the list, I go to action class first before page load by using . Then list is filled and form page displayed successfully. But don't show error message. :( – Min Naing Oo Apr 28 '13 at 18:16
The string returned by the action is used to determine what should be invoked, you have control over this. See update where an annotation demonstrates this. This requires the conventions plugin but you can just as easily configure this in struts.xml. Don't do that meta refresh! – Quaternion Apr 28 '13 at 18:32
http://img.viralpatel.net/2009/12/customer-page-validation-errors.png Please take a look. I want to show error like this when return "input" with xml validation. Please don't mind I'm hard to understand.. – Min Naing Oo Apr 29 '13 at 01:06
Find out how to "chain" back to the originating action. This should carry your errors back so the form is populated correctly and you get the error messages. – Quaternion Apr 29 '13 at 02:32

Roman C · Accepted Answer · 2013-07-22T15:14:47.410

All your problem have to be solved is repopulate the lists when you return from the validate() method. I guess your action extends the ActionSupport, if not then you should do it. Override the validate() method. There you should check hasActionErrors() and hasFieldErrors(). If any then repopulate lists. As a good practice you should separate the code that used to render JSP and reuse it in the validate method. After validate() the INPUT result returned without action execution.

validate struts2 form other than validation framework

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