Localizing Exception Messages using Spring

Question

I want to localize the exception messages thrown from POJO classes using Spring. I have a Spring MVC application through which I can add books. If the added book's title is null the implementation class throws an Exception. I want to localize this.

I know I can use the localeResolvers in the JSP pages and I have done that already. Can I leverage this to pick up localized error messages in the POJO? If so how do I inject the locale resolver (Cookie or Session) or locale which was set on the Cookie/Session into the POJO class?

addBook method throwing exception

    public void addBook(IBook book) throws Exception {
    if (book.getTitle() == null || book.getTitle() == "") {
        throw new Exception("Title is null");
    }

I want the throw new Exception("Title is null"); to be something like

String msg = rBundle.getMessage(propKey)
throw new Exception(msg);

where rBundle is a bundle object which knows its locale and the properties file from which it should pick the value for propKey

my controller class method which receives the form submission

@RequestMapping(method = RequestMethod.POST)
public String processSubmit(
        @RequestParam("siteLanguage") String siteLanguage,
        @ModelAttribute("book") Book book, BindingResult result,
        SessionStatus status, HttpServletRequest arg0) {
    logger.debug("Adding a Book");
    Locale loc = RequestContextUtils.getLocale(arg0);

    if (result.hasErrors()) {
        return "error.htm";
    } else {
        try {
            Author author = new Author("Gabriel Garcia Marquez");
            book.setAuthor(author);
            library.addBook(book);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return "redirect:home.htm";
    }
}

Is this possible? Or is it better I control the loading of java ResourceBundle for the respective locale.

Thanks

Answer 1

Why do you want to localize Exception?: I guess the exceptions are stored in a log file, the administrator should be able to read them, without knowledge of all the languages the users speak.

If you are talking about form validation, then have a look at spring form validation and jsr303 bean validation, both include concepts of localisation. (But both does not work with exceptions.)