MUlti Language support in JSP/Servlet

Question

How to provide multi language support through JSP/Servlet? How to include static data of different languages at run time on basis of language selected?

Answer 1

Can't you use the typical way of internationalization in java(properties ans resources) like:

Resource + "_" + localeLanguage + "_" + localeCountry + "_" + localeVariant

See this article to learn more.

Answer 2

There are several important aspects to this issue. The first part is determining each request's locale. You can use something like this:

HttpServletRequest req ...;
String browserLocale = req.getHeader("Accept-Language"); // typically something like 'en'

Next, you need to decide how to manage the site's localized content. The most Java-like (not necessarily the best) approach is to externalize all messages using a ResourceBundle. You can learn about the core Java facilities for I18N, G13N in their Isolating Locale Specific Data tutorial.

Using only this approach is quite poor in my opinion. Different languages' content size differently, match better with different layouts, etc. So you can completely eliminate resource bundles (if you don't have a lot of multi-locale data) or augment the approach by using XSLT or other templating that is locale specific.

One very performant but high-development overhead approach is to use a servlet filter to redirect traffic to language- (or locale-) specific subsites. In this case, anyone hitting http://my.domain.fake/xyz would get redirected to http://my.domain.fake/en/xyz

Finally, it is worth noting that most of the serious web frameworks have their own I18N support. Their approaches differ based on the framework philosophy.

Answer 3

In a "plain vanilla" JSP/Servlet application, the best solution is the JSTL fmt taglib. (just drop jstl-1.2.jar in /WEB-INF/lib) How to use it is covered in Sun Java EE tutorial part II chapter 7.

If you're using a MVC framework such as Sun JSF or Apache Struts, then you need to consult its specific documentation using keywords "internationalization" (i18n) or "localization" (l10n). In most cases they also provides specific tags for that, such as <f:loadBundle> in case of JSF, which in turn is covered in Sun Java EE tutorial part II chapter 15.

Those i18n tags already checks the default language/locale by ServletRequest#getLocale() (you don't need to do it "low-level" by checking the header as one suggested before --which would involve more work parsing the header as per the HTTP spec). You can let the user choose the language itself (dropdown?) and store it in the session scope and instruct those taglibs to use it. Here's an example with JSTL fmt taglib:

<fmt:setLocale value="${someSessionBean.locale}" />

..where ${someSessionBean.locale} can return en, en_US, en_UK, etc. Those are in turn used by the java.util.ResourceBundle API to load the localized text (you don't need to create/load the ResourceBundle itself, the taglibs already do that, just read the linked javadoc to learn a bit more about how it works).

If you want the language available as first pathinfo part of URL (such as http://example.com/en/, which is best for SEO), then you can best use a Filter for this which listens on /*, checks the pathinfo, splits the language part from it, stores/compares it as/with session value and forwards the request without language part in pathinfo further to the desired front controller. Same approach is also used in one of my last projects here.