Notes: International, notes International

Notes: International, notes International

Internationalization (I18N) indicates the first letter of the word, 18 indicates the length of the word, and N indicates the last letter of the word. Internationalization is also called Localization (L10N ).

Java internationalization is mainly achieved through the following three classes:

• Java. util. ResourceBundle: used to load a resource package
• Java. util. Locale: corresponds to a specific country/region and language environment.
• Java. text. MessageFormat: used to format messages

To internationalize a program, you must provide the resource files required by the program. The content of a resource file is composed of key-value pairs. The resource file can be named in three formats:

• Basename_language_country.properties
• Basename_language.properties
• Basename_properties

If the resource file contains non-Western characters, you must use the native2ascii tool that comes with JDK. The syntax format of this tool is as follows:

Native2ascii resource file name target resource file name

For example:

Native2ascii mess_zh_XXX.proerties mess_zh_CN.proerties

The Locale class can be used to obtain the regional environment (for example, Locale. ENGLISH, Locale. CHINESE, these constants return a Locale instance). You can also obtain the regional language environment used by the current system, or use the language and region to create a Locale object, the local language of Java is used when the International Standard Organization (ISO) defines the encoding, the local language is represented by the code of two lower-case letters, following the ISO-639-1; country code consists of two uppercase letters of code, followed by ISO-3166-1, the following table is commonly used code:

Language	Code	Country	Code
Chinese	Zh	China	CN
English	En	UnitedStates	US
Japan	Ja	Japan	JP

You can use the static method getAvailableLocales of Locale to obtain the Supported languages and countries. This method returns a Locale array containing the languages and countries supported by java. The Code is as follows:

Locale [] availableLocales = Locale. getAvailableLocales ();

For (Locale l: availableLocales ){

System. out. println ("Locale DisplayName =" + l. getDisplayName () + "Country =" + l. getCountry () + "Language ="

+ L. getLanguage ());

}

• Get Locale object
• Use the factory method to obtain the formatter object. When using the factory method, the NumberFormat class static method accepts a Locale type parameter. There are three factory methods: getNumberInstance (number) and getCurrencyInstance (currency) and getPercentInstance (percentage)
• Use this formatter object to complete formatting and parsing

Sample Code for formatting:

Locale deLocale = newLocale ("de", "DE ");

NumberFormat currFmt = NumberFormat. getCurrencyInstance (deLocale );

Double amt =123878.34;

String formatResult = currFmt. format (amt );

System. out. println ("amt =" + amt + "Format =" + formatResult );

If you want to read a number that is input or stored according to a Locale usage, you need to use the parse method.

Sample Code for parsing:

Localede Locale = newLocale ("de", "DE ");

NumberFormat currFmt = NumberFormat. getCurrencyInstance (deLocale );

Number input = currFmt. parse (formatResult );

Double parseAmt = input. doubleValue ();

System. out. println ("FormatAmt =" + formatResult + "ParseAmt =" + parseAmt );

Once the getBundle method locates a package, for example, "package name _ zh_CN", it will continue to search for the "package name _ zh" and "package name" packages, if these packages also exist, they are called "package name _ zh_CN" parent package in the resource level. If the package does not exist in the current package when searching for resources in the future, the parent package will be searched.