Java Locale
last modified January 10, 2023
In this article we show how to localize Java programs.
Internationalization is the process of designing an application so that it can be adapted to various languages and regions. Localization is the process of customizing applications for a specific region or language.
Locale represents a specific geographical, political, or cultural
region.
Locale-sensitive data include:
- messages
- dates and times
- numbers
- currencies
- measurements
- phone numbers
- names
- postal addresses
Java default locale
The default locale is determined with Locale.getDefault.
package com.zetcode;
import java.util.Locale;
public class LocaleEx {
public static void main(String[] args) {
var defLoc = Locale.getDefault();
System.out.println(defLoc.getDisplayCountry());
System.out.println(defLoc.getDisplayLanguage());
System.out.println(defLoc.getDisplayName());
System.out.println(defLoc.getISO3Country());
System.out.println(defLoc.getISO3Language());
System.out.println(defLoc.getLanguage());
System.out.println(defLoc.getCountry());
System.out.println("------------------------");
var skLoc = new Locale("SK", "sk");
System.out.println(skLoc.getDisplayCountry());
System.out.println(skLoc.getDisplayLanguage());
System.out.println(skLoc.getDisplayName());
System.out.println(skLoc.getISO3Country());
System.out.println(skLoc.getISO3Language());
System.out.println(skLoc.getLanguage());
System.out.println(skLoc.getCountry());
}
}
The program prints the attributes of a default locale and a Slovak locale.
var defLoc = Locale.getDefault(); System.out.println(defLoc.getDisplayCountry()); System.out.println(defLoc.getDisplayLanguage()); System.out.println(defLoc.getDisplayName());
We get the default locale and print the display country name, language, and name.
United States English English (United States) USA eng en US ------------------------ Slovakia Slovak Slovak (Slovakia) SVK slk sk SK
Java Locale constants
There are a few built-in locale constants such as Locale.US.
package com.zetcode;
import java.text.NumberFormat;
import java.util.Locale;
public class LocaleEx {
public static void main(String[] args) {
double n = 1240.35;
NumberFormat nf = NumberFormat.getInstance(Locale.US);
System.out.println(nf.format(n));
NumberFormat nf2 = NumberFormat.getInstance(Locale.FRANCE);
System.out.println(nf2.format(n));
NumberFormat nf3 = NumberFormat.getInstance(Locale.GERMAN);
System.out.println(nf3.format(n));
}
}
The program prints a number in Locale.US,
Locale.FRANCE, and Locale.GERMAN locales.
NumberFormat nf = NumberFormat.getInstance(Locale.US);
The NumberFormat.getInstance returns a general-purpose number
format for the specified locale.
System.out.println(nf.format(n));
We pass the value to the NumberFormat's format method.
1,240.35 1 240,35 1.240,35
Java Locale.Builder
Locales can be created with Locale.Builder.
package com.zetcode;
import java.text.NumberFormat;
import java.util.Locale;
public class LocaleEx {
public static void main(String[] args) {
double n = 1240.35;
var loc = new Locale.Builder()
.setLanguage("sk")
.setRegion("SK")
.build();
NumberFormat nf = NumberFormat.getInstance(loc);
System.out.println(nf.format(n));
var loc2 = new Locale.Builder()
.setLanguage("ja")
.setRegion("JP")
.build();
NumberFormat nf2 = NumberFormat.getInstance(loc2);
System.out.println(nf2.format(n));
}
}
The program localizes a value for Slovak and Japanese languages. The locales are created with a builder.
var loc = new Locale.Builder()
.setLanguage("sk")
.setRegion("SK")
.build();
A locale is built with the builder. We set the language with
setLanguage and the region with setRegion.
1 240,35 1,240.35
Java Locale constructor
There are three constructors for creating a Locale object.
Locale(String language) Locale(String language, String country) Locale(String language, String country, String variant)
We can specify language, country, and variants as parameters.
package com.zetcode;
import java.math.BigDecimal;
import java.text.NumberFormat;
import java.util.Locale;
public class LocaleEx {
public static void main(String[] args) {
var val = new BigDecimal("2530.45");
var skLoc = new Locale("sk", "SK");
var huLoc = new Locale("hu", "HU");
var ruLoc = new Locale("ru", "RU");
NumberFormat cf1 = NumberFormat.getCurrencyInstance(skLoc);
System.out.println(cf1.format(val));
NumberFormat cf2 = NumberFormat.getCurrencyInstance(huLoc);
System.out.println(cf2.format(val));
NumberFormat cf3 = NumberFormat.getCurrencyInstance(ruLoc);
System.out.println(cf3.format(val));
}
}
In the example, we print a currency value in Slovak, Hungarian, and Russian locales.
var val = new BigDecimal("2530.45");
For currency values, we should use BigDecimal.
NumberFormat cf1 = NumberFormat.getCurrencyInstance(skLoc);
To format a currency value, we use the
NumberFormat.getCurrencyInstance to which we pass the locale.
2 530,45 € 2 530,45 Ft 2 530,45 ₽
Java Locale format datetime
With Locale and DateTimeFormatter, we can format
datetime values.
package com.zetcode;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.FormatStyle;
import java.util.Locale;
public class LocaleEx {
public static void main(String[] args) {
var now = LocalDateTime.now();
var dtf1 = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM)
.withLocale(Locale.FRANCE);
System.out.println(now.format(dtf1));
var dtf2 = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM)
.withLocale(Locale.US);
System.out.println(now.format(dtf2));
var dtf3 = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM)
.withLocale(Locale.TRADITIONAL_CHINESE);
System.out.println(now.format(dtf3));
}
}
In the program, we format the current datetime in French, US, and Chinese locales.
var dtf1 = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM)
.withLocale(Locale.FRANCE);
We choose a datetime format style with ofLocalizedDateTime and
set the locale with withLocale.
21 oct. 2022, 19:45:10 Oct 21, 2022, 7:45:10 PM 2022年10月21日 下午7:45:10
Java Locale ResourceBundle
A resource bundle is a Java properties file that contains locale-specific data. We localize messages with resource bundles.
w1=Earth w2=ocean
This is the default properties file; it is typically in English language. We have two words inside the file.
w1=Erde w2=ozean
The words_de.properties file contains words in German language.
w1=Земля w2=океан
The words_ru.properties file contains words in Russian language.
package com.zetcode;
import java.util.Locale;
import java.util.ResourceBundle;
public class LocaleEx {
static public void main(String[] args) {
Locale[] locales = {
Locale.GERMAN,
new Locale("ru", "RU"),
Locale.ENGLISH
};
System.out.println("w1:");
for (Locale locale : locales) {
getWord(locale, "w1");
}
System.out.println("w2:");
for (Locale locale : locales) {
getWord(locale, "w2");
}
}
static void getWord(Locale curLoc, String key) {
ResourceBundle words = ResourceBundle.getBundle("resources/words", curLoc);
String value = words.getString(key);
System.out.printf("Locale: %s, Value: %s %n", curLoc, value);
}
}
In the code example, we print all the words used in three resource bundles.
ResourceBundle words = ResourceBundle.getBundle("resources/words", curLoc);
With the ResourceBundle.getBundle method, we get the bundle for the
currently used locale.
String value = words.getString(key);
From the bundle, we retrieve values with getString.
w1: Locale: de, Value: Erde Locale: ru_RU, Value: Земля Locale: en, Value: Earth w2: Locale: de, Value: ozean Locale: ru_RU, Value: океан Locale: en, Value: ocean
In this article we have shown how to localize Java programs.
List all Java tutorials.
