In Java/Spring, how to gracefully handle missing translation values?

Question

I\'m using Java + Spring for an international website.

The 2 languages are ZH and EN (Chinese and English).

I have 2 files: messages.properties (for English

Answer 1

You could create your own Custom MessageSource for this purpose.

Something like:

public class SpecialMessageSource extends ReloadableResourceBundleMessageSource {

      @Override
      protected MessageFormat resolveCode(String code, Locale locale) {
         MessageFormat result = super.resolveCode(code, locale);
         if (result.getPattern().isEmpty() && locale == Locale.CHINESE) {
            return super.resolveCode(code, Locale.ENGLISH);
         }
         return result;
      }

      @Override
      protected String resolveCodeWithoutArguments(String code, Locale locale) {
         String result= super.resolveCodeWithoutArguments(code, locale);
         if ((result == null || result.isEmpty()) && locale == Locale.CHINESE) {
            return super.resolveCodeWithoutArguments(code, Locale.ENGLISH);
         }
         return result;
      }
   }

and configure this messageSource bean in spring xml as

.....

Now to get resolved Label you will be invoking MessageSource's either of the below methods

String getMessage(String code, Object[] args, Locale locale);
String getMessage(String code, Object[] args, String defaultMessage, Locale locale);

resolveCode() will be called when your message label has arguments and you pass those arguments via args parameter like below
invalid.number= {0} is Invalid
and you invoke messageSource.getMessage("INVALID_NUMBER", new Object[]{2d}, locale)

resolveCodeWithoutArguments() will be called when your message label does not have arguments and you pass args parameter as null
validation.success = Validation Success
and you invoke messageSource.getMessage("INVALID_NUMBER", null, locale)