FormView is JSP taglib to manage postrender of JSP according to state (CREATE, READ, UPDATE,...). With Formview you develop just ONE JSP to manage READ-ONLY and READ-WRITE form. For instance, on CREATE state HTML inputs will be READ-WRITE and on READ state inputs will be READ-ONLY. You can use FormView with HTML or any JSP taglib (struts, struts-layout, jsp...) that you want postrender by FormView. With FormView you can customize input according to state (add attribute readonly to HTML input or replace it by value when form must be displayed to READ state). Formview can be plugged with Struts Validator to use information about validation to update HTML according to validation (eg : add maxlength attribute to HTML input if form must be validate by maxlength, add calendar if input must be date).
You can too manage state with sub form, in order to set a state for particulary piece of your page. Sub form is interesting for example, when you want manage state for a particulary tab of tabs. For example, set READ-ONLY state for all inputs of the first tab, and set READ-WRITE state for all inputs of the second tab. FormView has usecase WAR, whith an example of tabs which use jsptabControl Taglib (see http://jsptabcontrol.sourceforge.net/).
You can manage error after validation of your form. So you can :
- add style class error to the field which has error.
- set focus to the first field which has error.