How to add error on Spring MVC simpleformcontroller? - spring

Question

I have this problem in my Spring MVC 2.5 apps and I am not sure what should I do.
Here is my code:
public class AddStationController extends SimpleFormController {
private SimpleStationManager stationManager;
protected ModelAndView onSubmit(HttpServletRequest request,
HttpServletResponse response, Object command, BindException errors)
throws Exception {
StationDetails detail = (StationDetails) command;
//add to DB
int return = stationManager.addStation(detail);
//return value: 1 = successful,
// if not = unsuccessful
if(return != 1){
//how can I add error so that when I display my formview ,
//I could notify the user that saving to the db is not successful?
showform();
}
return new ModelAndView("redirect:" + getSuccessView());
}
}
How is it possible to add some message when I display my formview again so that I could tell the user that adding the station was not successful?
And how to handle that in my jsp?

Answer 1

I at first thought you might want to use Validators but instead I think you can do the following:
public class AddStationController extends SimpleFormController {
private SimpleStationManager stationManager;
protected ModelAndView onSubmit(HttpServletRequest request,
HttpServletResponse response, Object command, BindException errors)
throws Exception {
StationDetails detail = (StationDetails) command;
//add to DB
int return = stationManager.addStation(detail);
//return value: 1 = successful,
// if not = unsuccessful
if(return != 1){
//Account for failure in adding station
errors.reject("exception.station.submitFailure", "Adding the station was not successful");
showform(request, response, errors);
}
return new ModelAndView("redirect:" + getSuccessView());
}
}
Then in your JSP you can do the following:
<form:errors path="*">
Then any errors you bind will show up there.

Answer 2

There are a couple ways to do that. I prefer not to use the showForm() method b/c I want more control. So I do one of the following, I'm sure there will be several alternative answers given for your question.
If you don't want to fail b/c of a specific field you can just send back an error on the model like this:
ModelAndView mav = new ModelAndView(this.getFormView());
mav.addObject(this.getCommandName(), command);
mav.addObject("errorMessage", "The thing you tried to do failed");
return mav;
Then in your jsp you would do this:
<c:if test="${not empty errorMessage}">
${errorMessage}
</c:if>
If you have a specific field that has caused the error you can attach an error to the specific field like this (this rejects the length of a field called "alternateid":
errors.rejectValue("alternateId", "longerThan",
new Object[] { Integer.valueOf(2) }, "Please enter at least two characters.");
ModelAndView mav = new ModelAndView(this.getFormView());
mav.addAllObjects(errors.getModel());
mav.addObject(this.getCommandName(), command);
return mav;
Then in your jsp you would use the form tag library and do this:
<form:errors path="alternateId"/>
That's assuming you're using the spring form tag library.