Servlet internationalization

Before we begin, let’s take a look at three important terms:

Internationalization (i18n): this means that a website provides different versions of the content translated into the language or nationality of the visitor.
Localization (l10n): this means adding resources to the site to adapt it to a specific geographical or cultural area, such as the translation of the site into Hindi.
Locale (locale): this is a special cultural or geographical area. It usuallyrefers to a language symbol followed by an underscore and a country symbol.For example, “en_US” represents the English locale for US.

There are some considerations when building a global website. This tutorial will not cover the full details of these considerations, but it will show you how to make web pages render in different languages through differentiated positioning (that is, locales).

Servlet can pick up the appropriate version of the website according to the requester’s regional settings, and provide the corresponding version of the website according to the local language, culture and needs. The following is``request`` object to return to Locale the method of the.

java.util.Locale request.getLocale()

Detect locale

Important locale methods are listed below that you can use to detect the requester’s geographic location, language, and locale. All of the following methods display the country and language names set in the requestor’s browser.

Serial number	Method & description
1	String getCountry () this method returns the country code for the locale in ISO 3166 format in 2 uppercase letters.
2	String getDisplayCountry () this method returns the name of the country appropriate for the locale to be displayed to the user.
3	String getLanguage () this method returns the language code for the locale in lowercase ISO 639 format.
4	String getDisplayLanguage () this method returns the name of the language appropriate for the locale to be displayed to the user.
5	String getISO3Country () this method returns the three-letter abbreviation of the country in which the locale is set.
6	String getISO3Language () this method returns a three-letter abbreviation for the locale’s language.

Example

This example demonstrates how to display the language of a request and the relevant country:

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.Locale;

public class GetLocale extends HttpServlet{

  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
            throws ServletException, IOException
  {
      // Get the client's regional settings
      Locale locale = request.getLocale();
      String language = locale.getLanguage();
      String country = locale.getCountry();

      // Set response content type
      response.setContentType("text/html;charset=UTF-8");
      PrintWriter out = response.getWriter();

      String title = "Detection Area Settings";
      String docType = "<!DOCTYPE html> \n";
      out.println(docType +
        "<html>\n" +
        "<head><title>" + title + "</title></head>\n" +
        "<body bgcolor=\"#f0f0f0\">\n" +
        "<h1 align=\"center\">" + language + "</h1>\n" +
        "<h2 align=\"center\">" + country + "</h2>\n" +
        "</body></html>");
  }
}

Language setting

Servlet can export pages written in Western European languages such as English, Spanish, German, French, Italian, Dutch, and so on. Here, in order to display all characters correctly, it is very important to set the Content-Language header.

The second point is to use the HTML entity to display all special characters, such as “& # 241;” for “ñ”, “& # 161;” for “”, as follows:

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.Locale;

public class DisplaySpanish extends HttpServlet{

  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
            throws ServletException, IOException
  {
    // Set response content type
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();
    // Set Spanish language code
    response.setHeader("Content-Language", "es");

    String title = "En Espa&ntilde;ol";
    String docType = "<!DOCTYPE html> \n";
     out.println(docType +
     "<html>\n" +
     "<head><title>" + title + "</title></head>\n" +
     "<body bgcolor=\"#f0f0f0\">\n" +
     "<h1>" + "En Espa&ntilde;ol:" + "</h1>\n" +
     "<h1>" + "&iexcl;Hola Mundo!" + "</h1>\n" +
     "</body></html>");
  }
}

Locale-specific date

You can use the java.text.DateFormat class and its static methods getDateTimeInstance() to format locale-specific dates and times. The following example shows how to format a date specific to a given locale:

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.Locale;
import java.text.DateFormat;
import java.util.Date;

public class DateLocale extends HttpServlet{

  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
            throws ServletException, IOException
  {
    // Set response content type
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();
    // Get the client's regional settings
    Locale locale = request.getLocale( );
    String date = DateFormat.getDateTimeInstance(
                                  DateFormat.FULL,
                                  DateFormat.SHORT,
                                  locale).format(new Date( ));

    String title = "Regional specific dates";
    String docType = "<!DOCTYPE html> \n";
      out.println(docType +
      "<html>\n" +
      "<head><title>" + title + "</title></head>\n" +
      "<body bgcolor=\"#f0f0f0\">\n" +
      "<h1 align=\"center\">" + date + "</h1>\n" +
      "</body></html>");
  }
}

Locale-specific currency

You can use the java.text.NumberFormat class and its static methods getCurrencyInstance() to format numbers (such as long type or double type) is a locale-specific currency. The following example shows how to format a currency specific to a given locale:

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.Locale;
import java.text.NumberFormat;
import java.util.Date;

public class CurrencyLocale extends HttpServlet{

  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
            throws ServletException, IOException
  {
    // Set response content type
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();
    // Get the client's regional settings
    Locale locale = request.getLocale( );
    NumberFormat nft = NumberFormat.getCurrencyInstance(locale);
    String formattedCurr = nft.format(1000000);

    String title = "Currency specific to regional settings";
    String docType = "<!DOCTYPE html> \n";
      out.println(docType +
      "<html>\n" +
      "<head><title>" + title + "</title></head>\n" +
      "<body bgcolor=\"#f0f0f0\">\n" +
      "<h1 align=\"center\">" + formattedCurr + "</h1>\n" +
      "</body></html>");
  }
}

Percentage specific to locale

You can use the java.text.NumberFormat class and its static methods getPercentInstance() to format the percentage specific to the locale. The following example shows how to format a percentage specific to a given locale:

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.Locale;
import java.text.NumberFormat;
import java.util.Date;

public class PercentageLocale extends HttpServlet{

  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
            throws ServletException, IOException
  {
    // Set response content type
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();
    // Get the client's regional settings
    Locale locale = request.getLocale( );
    NumberFormat nft = NumberFormat.getPercentInstance(locale);
    String formattedPerc = nft.format(0.51);

    String title = "Region specific percentage";
    String docType = "<!DOCTYPE html> \n";
      out.println(docType +
      "<html>\n" +
      "<head><title>" + title + "</title></head>\n" +
      "<body bgcolor=\"#f0f0f0\">\n" +
      "<h1 align=\"center\">" + formattedPerc + "</h1>\n" +
      "</body></html>");
  }
}