CODEWITHSUNDEEP
javainternationalization
user1253847
user1253847

Reputation: 5451

How to set the Locale Value based on the country the user belongs to

Currently my J2EE Application supports these below countries 

MessagesBundle_en_GB.properties (United Kingdom )
MessagesBundle_en_US.properties (United States )
MessagesBundle_it_IT.properties (Italy )
MessagesBundle_pt_BR.properties (Brazil )
MessagesBundle_sv_SE .properties (Sweden)

So i made a properties files for all these countries above and defined the Key value pairs in it . I am using Resource Bundle for this concept .

And the way i will be accessing the key name is this way 

bundle.getString("userName"));
bundle.getString("Mobile"));

Now my question is ,

How can i set the Locale value inside the JSP Page , because the user might belong any of the country as mentioned above

Please let me know , thank you very much

// This one is hardcoded , how can i set this dynamically ??

ResourceBundle bundle = ResourceBundle.getBundle("MessagesBundle", Locale.UK);

Upvotes: 0

Views: 1760

Answers (3)

Paweł Dyda
Paweł Dyda

Reputation: 18662

First thing first: you may use ResourceBundle.getBundle(Locale) in your back-end code. However, you should never use this in the JSP Page directly. You should use JSTL instead. Now, let's get into details.

There are two reasons why it is not necessary the good idea to use ResourceBundle directly. One is related to this:

<% 
try {
  ResourceBundle rb = ResourceBundle.getBundle("messages", locale);
} catch (MissingResourceException mre) {
   // LOG THIS!
}
%>

This looks pretty ugly, doesn't it? That's because you have to beware of MissingResourceException that will be thrown if there is no bundle for base name you are looking for. To make matters worse, the same exception might be thrown if there is no key in the given scenario:

rb.getString("key");

So you also need to take this into account:

<% 
try {
  rb.getString("key");
} catch (MissingResourceException mre) {
   // LOG THIS!
}
%>

How does it look?
Of course you can derive from ResourceBundle and override these methods so they won't throw an exception, but this is substantially more work than just this:

<fmt:setLocale value="fr_CA" scope="session"/>
<fmt:bundle basename="com.taglib.weblog.Greeting">
<fmt:message key="com.taglib.weblog.Greeting.greeting">

This is the reason you should use JSTL with JSP. Read more about how to use JSTL for i18n in this article.

Now, your original question was about language negotiation (W3C term), or Locale detection if you prefer. How to do that in JSP application?
The easiest and most typical scenario is to read the contents of HTTP's Accept-Language header. In Java Servlet world that means calling ServletRequest's getLocale() or getLocales() method and assign to variable in HttpSession object, which is accessible from JSP page. If you wonder how to access HttpSession on the servlet side, there is a getSession() method.

That works if you have direct access to Servlet. If you don't you need to create (or assign existing) Locale filter which will do all that for you. As you may imagine, this is fairly common scenario. That's the reason people already written (long time ago) necessary classes. You can find in few frameworks, let me notably mention Spring Framework.
I know it might sound strange, but if you are looking for simple solution, learning and using common web framework (i.e. Spring MVC) is better that re-inventing the wheel. I know that learning curve might be a bit steep, but it is worth it.

Upvotes: 0

Subhrajyoti Majumder
Subhrajyoti Majumder

Reputation: 41200

use ResourceBundle.getBundle(BUNDLE_NAME).getString(key); to access the Strings.

when updating the Default Locale e.g. via Locale.setDefault(<REQUIRED_LOCALE>); clear the Resourcebundle cache: ResourceBundle.clearCache();

the next call of ResourceBundle.getBundle(BUNDLE_NAME).getString(key); should the return the localized String of the chosen Locale.

Upvotes: 1

AlexR
AlexR

Reputation: 115328

The simplest way to do it is to implement HttpFilter. Call it for example LocaleHttpFilter. It should be mapped to/*` in your web.xml, so it will be called every time the request arrives to your application.

The filter will discover your request and decide what should be the current locale. It may base its decision on URL parameters, HTTP headers, GeoIP lookup etc. Once it decided about the locale it should call:

Locale.setDefault(locale)

Then you can use

ResourceBundle.getBundle("MessageBundle").getString("hello");

at any place in your code. This line will return value of string "hello" according to the current locale that was set into the filter.

Upvotes: 0

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