In this article we will discuss about the Locale class from java.util package. The Locale is used to make the system relevant and usable for the users from different cultures. In other words, it is used to customize the system for different people of different region, culture and language.
A Locale object represents a specific geographical, political, or cultural region.
Let’s discuss about the Locale class and how to create, query and use a Locale object.
1. Locale Instantiation
There are many ways to create a Locale object. As of JDK 7, there are four ways to create a Locale object. In the following example, we will see different ways of creating it and differences between them.
1.1 Using constructor
1.1a. Locale(String language): Construct a locale from a language code. For e.g. “fr” is a language code for French.
1.1.b. Locale(String language, String country): When you have a language code and a country, you can use this constructor with two parameters that takes a language as first parameter and a country as second parameter to create a locale object.
1.1c. Locale(String language, String country, String variant): Construct a locale from language, country and variant. Any arbitrary value can be used to indicate a variation of a Locale.
1.2 Using Builder method
From JDK 7 releases, the Locale provides a Builder to create an instance of the Locale class. Using Locale.Builder you can instantiate an object that conforms to BCP 47 syntax.
Locale localeFromBuilder = new Locale.Builder().setLanguage("en").setRegion("GB").build();
1.3 Using forLanguageTag method:
forLanguageTag (String languageTag) returns a locale for the specified IETF BCP 47 language tag string. If the specified language tag contains any ill-formed subtags, the first such subtag and all the following subtags are ignored.
Locale forLangLocale = Locale.forLanguageTag("en-GB");
1.4 Locale constants
Java provides a set of pre-defined constants for some languages and countries. If a language constant is specified, then the regional portion of that locale is undefined.
Locale localeCosnt = Locale.FRANCE;
LocaleExample.java
package com.javacodegeeks.corejava.util;
import java.util.Locale;
public class LocaleExample {
public static void main(String[] args) {
// Creates a locale object using one parameter to constructor
Locale locale = new Locale("fr");
System.out.println("locale: "+locale);
// Create a locale object using two parameters constructor
Locale locale2 = new Locale("fr", "CANADA");
System.out.println("locale2: "+locale2);
// Create a locale object using three parameters constructor
Locale locale3 = new Locale("no", "NORWAY", "NY");
System.out.println("locale3: "+locale3);
// A local object from Locale.Builder
Locale localeFromBuilder = new Locale.Builder().setLanguage("en").setRegion("GB").build();
System.out.println("localeFromBuilder: "+localeFromBuilder);
//Locale from forLanguageTag method
Locale forLangLocale = Locale.forLanguageTag("en-GB");
System.out.println("forLangLocale: "+forLangLocale);
//Using Locale Contant
Locale localeCosnt = Locale.FRANCE;
System.out.println("localeCosnt: "+localeCosnt);
}
}
- If we run the above code, we will have the following results:
locale: fr locale2: fr_CANADA locale3: no_NORWAY_NY localeFromBuilder: en_GB forLangLocale: en_GB localeCosnt: fr_FR
Although, you can use any of these ways to create a locale object. But it is recommended to use forLanguageTag and Locale.Builder methods. The reason is these two methods return a locale for the specified IETF BCP 47 language tag string. BCP 47 imposes syntax restrictions that are not imposed by Locale’s constructors. This means that conversions between some Locales and BCP 47 language tags cannot be made without losing information.
2. Methods
In this section, we will discuss about some of the important methods of the Locale class. You can use these methods on a locale object to get some information about the Locale.
LocaleMethodExample.java
package com.javacodegeeks.corejava.util;
import java.util.Locale;
public class LocaleMethodExample {
public static void main(String[] args) {
// Getting a default locale object
Locale locale = Locale.getDefault();
System.out.println("Default Locale: "+locale);
// Getting all available locales from current instance of the JVM
Locale []availableLocale = Locale.getAvailableLocales();
for(Locale aLocale : availableLocale){
System.out.println("Name of Locale: "+aLocale.getDisplayName());
System.out.println("Language Code: "+aLocale.getLanguage()+", Language Display Name: "+aLocale.getDisplayLanguage());
System.out.println("Country Code: "+aLocale.getCountry()+", Country Display Name: "+aLocale.getDisplayCountry());
if(!aLocale.getScript().equals("")){
System.out.println("Script Code: "+aLocale.getScript()+", Script Display Name: "+aLocale.getDisplayScript());
}
if(!aLocale.getVariant().equals("")){
System.out.println("Variant Code: "+aLocale.getVariant()+", Variant Display Name: "+aLocale.getDisplayVariant());
}
System.out.println("****************************************************************");
}
}
}
- If we run the above code, we will have the following results:
Default Locale: en_US Name of Locale: Malay (Malaysia) Language Code: ms, Language Display Name: Malay Country Code: MY, Country Display Name: Malaysia **************************************************************** Name of Locale: Arabic (Qatar) Language Code: ar, Language Display Name: Arabic Country Code: QA, Country Display Name: Qatar **************************************************************** Name of Locale: Icelandic (Iceland) Language Code: is, Language Display Name: Icelandic Country Code: IS, Country Display Name: Iceland **************************************************************** Name of Locale: Serbian (Latin,Montenegro) Language Code: sr, Language Display Name: Serbian Country Code: ME, Country Display Name: Montenegro Script Code: Latn, Script Display Name: Latin **************************************************************** Name of Locale: Thai (Thailand,TH) Language Code: th, Language Display Name: Thai Country Code: TH, Country Display Name: Thailand Variant Code: TH, Variant Display Name: TH **************************************************************** .......[output truncated]
Please note that in the above example, we have printed only that script and variant which are specified for the locale object.
Locale.getDefault() gets the current value of the default locale for current instance of the Java Virtual Machine. The Java Virtual Machine sets the default locale during startup based on the host environment.
Locale.getAvailableLocales() returns an array of all available locales installed on that particular JVM machine.
String getDisplayName() is an instance method which returns the name of the locale object (appropriate to display) in string form. The name contains values returned by getDisplayLanguage(), getDisplayScript(),getDisplayCountry(), and getDisplayVariant() methods .
String getLanguage() returns the language code of the locale object.
String getDisplayLanguage() returns the name of the locale’s language. It shows an appropriate name for display to the user.
String getCountry() returns the country/region code for this locale, which should either be the empty string, an uppercase ISO 3166 2-letter code, or a UN M.49 3-digit code.
String getDisplayCountry() returns the name of the locale’s country. It shows an appropriate name for display to the user.
String getScript() returns the script code for this locale. It should either be the empty string or an ISO 15924 4-letter script code. The first letter is uppercase and the rest are lowercase, for example, ‘Latn’, ‘Cyrl’.
String getDisplayScript() returns the name of the locale’s script appropriate for display to the user.
String getVariant() returns the variant code, or the empty string if none is defined.
String getDisplayVariant() returns a name for the locale’s variant code that is appropriate for display to the user.
3. Locale sensitive classes
The Locale is the mechanism for identifying the kind of object that you would like to get. Java provides certain classes which provide locale specific operations. For example, they provide methods to format values that represent dates, currency and numbers according to a specific locale. These classes are known as Locale sensitive classes.
In the following example, we will use NumberFormat, Currency, and DateFormat classes to illustrate about locale sensitive operations.
LocaleSensitiveExample.java
package com.javacodegeeks.corejava.util;
import java.text.DateFormat;
import java.text.NumberFormat;
import java.util.Currency;
import java.util.Date;
import java.util.Locale;
public class LocaleSensitiveExample {
public static void main(String[] args) {
long number = 5000000L;
NumberFormat numberFormatDefault = NumberFormat.getInstance();
System.out.println("Number Format using Default Locale: "+numberFormatDefault.format(number));
NumberFormat numberFormatLocale = NumberFormat.getInstance(Locale.ITALY);
System.out.println("Number Format using ITALY Locale: "+numberFormatLocale.format(number));
NumberFormat numberFormatDefaultCurrency = NumberFormat.getCurrencyInstance();
System.out.println("Currency Format using Default Locale: "+numberFormatDefaultCurrency.format(number));
NumberFormat numberFormatLocaleCurrency = NumberFormat.getCurrencyInstance(Locale.ITALY);
System.out.println("Currency Format using ITALY Locale: "+numberFormatLocaleCurrency.format(number));
Currency currency = Currency.getInstance(Locale.CHINA);
System.out.println(currency.getDisplayName()+" ("+currency.getCurrencyCode()+") "+currency.getDisplayName());
Date currentDate = new Date();
DateFormat dateFormat = DateFormat.getDateInstance(DateFormat.FULL, Locale.GERMAN);
System.out.println("Date Format in German Locale: "+dateFormat.format(currentDate));
}
}
- If we run the above code, we will have the following results:
Number Format using Default Locale: 5,000,000 Number Format using ITALY Locale: 5.000.000 Currency Format using Default Locale: $5,000,000.00 Currency Format using ITALY Locale: € 5.000.000,00 Chinese Yuan (CNY) Chinese Yuan Date Format in German Locale: Samstag, 31. Mai 2014
In the above example, we have used the getInstance() static method to get the instance about the respective class. The getInstance() methods used in two variety one without locale (which uses the default locale set in the current instance of the JVM) and another with a Locale as its parameter.
You can clearly see the differences in the output due to difference in the locale object used.
This was an example of how to use the Locale class and some of its basic methods.
4. Download the source code
You can download the source code of this example from here: LocaleExample.zip
Hi, NIce article.
I am looking for somethin like: IF I enter some text then it should change the text from one langue to another .For exmaple, “Hello” is in english , I want the same in Chineese.
Is that possible .I was looking for string formater class.