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Java Internationalization Programming
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The 'ResourceBundle' class loads resource data according to the specified locale (if no one specified, the system locale will be used), and the localized data such as messages, lables, and images can be switched to user locale ones by this class.

ResourceBundle wwnaviBundle = 
    ResourceBundle.getBundle("wwnavi_rs"); <-- *"wwnavi_rs" is a property file name (see the next section).

1. Resource File (Property File) Creation
   • Messages collected from programs can be described in property files (.properties).
     The following is a sample generated by World Wide Navi.
     
     wwnavi_rs.properties

     #$NLS-WWNAVI 2008-05-24T20:26:09+0900
     #Sat May 24 20:26:09 JST 2008
     me.tree.MainPanel.8=This is node5
     me.tree.MainPanel.7=This is node4
     

     *You have to be careful about describing non-ASCII characters. You cannot describe non-ASCII characters directly in a Java property file. To describe non-ASCII characters, you have to put them in a text file and then convert it to a .properties file with the command 'native2ascii' in JDK.

     The next steps are for describing Japanese characters in a property file. This is a sample generated by World Wide Navi.
     
     wwnavi_rs_ja.properties.UTF-8 (UTF-8 text file)

     #$NLS-WWNAVI 2008-05-24T20:26:09+0900
     #Sat May 24 20:26:09 JST 2008
     me.tree.MainPanel.8=これはノード5
     me.tree.MainPanel.7=これはノード4
     

     Create a property file with the 'native2ascii' command.

     native2ascii -encoding UTF-8 wwnavi_rs_ja.properties.UTF-8 \
         wwnavi_rs_ja.properties
     

     wwnavi_rs_ja.properties (property file generated by the step above.)

     #$NLS-WWNAVI 2008-05-24T20:26:09+0900
     #Sat May 24 20:26:09 JST 2008
     me.tree.MainPanel.8=\u3053\u308c\u306f\u30ce\u30fc\u30c95
     me.tree.MainPanel.7=\u3053\u308c\u306f\u30ce\u30fc\u30c94
     

2. Describe the Message Loading.
   • Embed the message loading codes in the string literal positions:

     JOptionPane.showMessageDialog(null, 
         wwnaviBundle.getString("me.tree.MainPanel.4")); <-- *Loading the message of the key 'me.tree.MainPanel.4'.
     

3. The location of the .properties files
   • .properties files are placed in the directory set in CLASSPATH. Generally, they are on the top directory of the class packages to load. The rules for filenames are described below.

     resource-bundle name (e.g. "wwnavi_rs") + "_" + language name (e.g. "ja")
     

     The default resource is a property file with the same name as the resource bundle. (*Please refer to the Java API Documentation for the details of property file naming rules.)
     
     For example, run the class 'MainPanel.class' according to the settings below.

     java -cp . me.tree.MainPanel <-- *CLASSPATH is the current directory
     export LANG=ja_JP.UTF-8 <-- *Change the language to Japanese.
     java -cp . me.tree.MainPanel <-- *CLASSPATH is the current directory
     

     The locations of the .properties files will be the following:

     me/tree/MainPanel.class <-- *Class file
     wwnavi_rs.properties <-- *Default property-file
     wwnavi_rs_ja.properties <-- *Japanese property-file
     

     *If you call the ResourceBundle in JSP, The default CLASSPATH will be '../WEB-INF/classes' and the property files need located in it.

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