Converts a String to a Locale : Locales « I18N « Java Tutorial

// Copyright 2008 The Apache Software Foundation
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.

import java.util.Locale;

 * Contains code borrowed from <a href="">commons-lang</a>.
public class LocaleUtils
     * Converts a String to a Locale. <p/> This method takes the string format of a locale and creates the
     * locale object from it. <p/>
     * <pre>
     *   LocaleUtils.toLocale("en")         = new Locale("en", "")
     *   LocaleUtils.toLocale("en_GB")      = new Locale("en", "GB")
     *   LocaleUtils.toLocale("en_GB_xxx")  = new Locale("en", "GB", "xxx")   (#)
     * </pre>
     * <p/> (#) The behaviour of the JDK variant constructor changed between JDK1.3 and JDK1.4. In JDK1.3, the
     * constructor upper cases the variant, in JDK1.4, it doesn't. Thus, the result from getVariant() may vary depending
     * on your JDK. <p/> This method validates the input strictly. The language code must be lowercase. The
     * country code must be uppercase. The separator must be an underscore. The length must be correct. 
     * @param input the locale String to convert, null returns null
     * @return a Locale, null if null input
     * @throws IllegalArgumentException if the string is an invalid format
    public static Locale toLocale(String input)
        if (input == null)
            return null;

        int len = input.length();
        if (len != 2 && len != 5 && len < 7)

        char ch0 = input.charAt(0);
        char ch1 = input.charAt(1);

        if (ch0 < 'a' || ch0 > 'z' || ch1 < 'a' || ch1 > 'z')

        if (len == 2)
            return new Locale(input, "");

        if (input.charAt(2) != '_')

        char ch3 = input.charAt(3);
        if (ch3 == '_')
            return new Locale(input.substring(0, 2), "", input.substring(4));

        char ch4 = input.charAt(4);
        if (ch3 < 'A' || ch3 > 'Z' || ch4 < 'A' || ch4 > 'Z')

        if (len == 5)
            return new Locale(input.substring(0, 2), input.substring(3, 5));

        if (input.charAt(5) != '_')

        return new Locale(input.substring(0, 2), input.substring(3, 5), input.substring(6));

    private static void fail(String input)
        throw new IllegalArgumentException(String.format("Unable to convert '%s' to a Locale instance.", input));


13.1.2.Listing All Available Locales
13.1.3.Get the 2-letter country code; may be equal to ""
13.1.4.Get localized name suitable for display to the user
13.1.5.Setting the Default Locale on the command line
13.1.6.Set only language code on the command line
13.1.7.Set language and country code on the command line
13.1.8.Change the default locale is to call Locale.setDefault():
13.1.9.Set the default locale to pre-defined locale
13.1.10.Set the default locale to custom locale
13.1.11.format date for a Locale
13.1.12.Get a list of country names
13.1.13.Set a default Locale
13.1.14.New locales in Java 6
13.1.15.Locale Sensitive Services SPI
13.1.16.Japanese ImperialCalendar
13.1.17.Use Locale constant
13.1.18.Load Resource Bundle based on Locale Name
13.1.19.Get Display Country for default locale
13.1.20.Get ISO3 Language for default locale
13.1.21.Get Display Name for default locale
13.1.22.Get Display Variant for default locale
13.1.23.Constant Locale Usage
13.1.24.Map using Locale objects as keys
13.1.25.Calculate the postfix to append to a filename to load the correct single filename for that Locale.
13.1.26.Calculate the postfixes along the search path from the base bundle to the bundle specified by baseName and locale.
13.1.27.Converts a String to a Locale
13.1.28.Returns the parent locale of a given locale.