How to re-populate form fields on a jsp page after failed server validation

I have a very simple Java MVC web application and am using a servlet to handle form validation. If the form is validated, the request is forwarded to the appropriate view. However, if the form fails validation, the 开发者_JAVA百科request is forwarded back to the form, which then displays the appropriate error message(s).

My question is this -- what is the most efficient way to re-populate all of the form fields with the data that was originally entered in the form by the user?

I am not using an MVC framework, just simple HttpServlets as the controller with .jsp as the view.

The easiest and probably least effort is to just use

<input name="foo" type="text" value="${param.foo}"/>

This should default to "" when the user first visits the form.

A little more can be done to create a custom tag which binds to the request. However this is probably not the solution you were looking for.

Edit: You may want to use <c:out value="${param.foo}"/> to protect against XSS attack.

Pass the fields back to the jsp as part of the request object. request.setAttribute(..)

Use those attributes to set the form fields.