Question

I have a PropertyEditor in order to translate ids into Persons, with it’s setAsText (String text) as follows:

public void setAsText(String text) throws IllegalArgumentException {
    try {
        int id = Integer.parseInt(text);
        Person person = peopleService.get(id);
        this.setValue(person);
    }
    catch (NumberFormatException ex) {
        // ...
        throw new IllegalArgumentException("Not a number!: " + text);
    }
    catch (PersonNotFoundExcetion ex) {
        // ...
        throw new IllegalArgumentException("Impossible to get Person: " + text);
    }
}

And my PeopleController has a method as follows:

@RequestMapping("/getPerson")
public void ver (@RequestParam Person person, Model model) {
    model.addAttribute (person);
    // ...
}

I want to catch the IllegalArgumentException in order to show a friendly message to the user, such as “Sorry, the Person you are looking for isn’t here”, but I don’t know where to do that…

Thanks!

Answer 1

General exception handling can be done in this way:

@ExceptionHandler(Exception.class)
@ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
public String handleAllExceptions(Exception e) {
  return "redirect:/error.html"; /* use the correct view name */
}

More specfic you could use BindingResult

@RequestMapping(value = "/datedata", method = RequestMethod.POST)
public String create(
    @ModelAttribute("datedata") final DateData datedata,
    final BindingResult result) {

    if (result.hasErrors()) {
        return "datedata/create";
    } else {
        ...
        return "myView";
    }
 }

But I guess this works only for “Forms” (ModelAttribute)

In my humble opinion it is not a good idea to let Spring handle validaten of user input by property editors. I would strongly recommend to use the Form way: Build a command object with a STRING field an use a validator on it.