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Localization / Internationalization - Non ASCII Characters in JSP Pages
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This chapter explains:
- How characters travel from JSP files to browser screens.
- How ASCII characters work in JSP pages.
- How to present non ASCII characters in HTML documents.
- How to enter non ASCII charactetrs in Java strings and contole the output encodings.
- How Java string works with byte sequences encoded for a local language.
- How Java string works with Unicode codes - local language independent.
- How to enter non ASCII characters as static HTML text.
- How static HTML text works in HTML pages
- How static HTML text works in JSP pages with standard syntax.
- How static HTML text works in JSP pages with XML syntax.
- How to supporting characters from multiple languages.
For more notes on non ASCII codes and Java program localization, see my other books:
"Herong's Notes on Unicode" and "Herong's Notes on JDK".
Characters Traveling from JSP Files to Browser Screens
Handling non ASCII characters in JSP files correctly is not an easy task.
I have seen many messages on the Wep in this area reporting various frustrating situations.
One main reason is that text entered in a JSP file must travel through many steps
before being displayed by a browser on a screen.
The following diagram illustrates steps that characters must travel from a JSP
file to a browser screen, and computing technologies that are used at different steps:
0. Key Sequences from Keyboard
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|- Text Editor
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1. JSP File
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|- XML Parser
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2. Java Source File
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|- Java Compiler
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3. Java Class File
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|- Java Virtual Machine
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4. HTML Document
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|- Web Server
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5. HTTP Response
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|- Internet TCP/IP Connection
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6. HTTP Response
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|- Web Browser
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7. Characters on the Screen
Since all computing technologies are using ASCII encoding by default, text of
ASCII characters can safely travel through those steps without any issues.
However, for non ASCII characters, we have to watch out each steps carefully
to make sure that characters are not damaged, and/or decoded correctly if encoded.
ASCII Characters in JSP Pages
As I mentioned earlier, ASCII characters can travel from JSP files to browsers
easily without any trouble. Here is a simple JSP file with ASCII characters only:
<?xml version="1.0"?>
<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page"
xmlns:c="http://java.sun.com/jstl/core" version="1.2">
<!-- HelpASCII.jsp
Copyright (c) 2002 by Dr. Herong Yang
-->
<jsp:directive.page contentType="text/html"/>
<html><body>
<b>Help</b><br/>
<p>This is a very simple help page...</p>
</body></html>
</jsp:root>
If you view this page with a browser, you will get two lines of characters:
Help
This is a very simple help page...
They are exactly what I entered into the JSP file.
Presenting Non ASCII Characters in HTML Documents
In order to ensure non ASCII characters entered in JSP files to show up on
browser screens correctly, we need to understand how non ASCII characters
are processed from one step to the other. The processing steps can be grouped into
two parts:
- Outputing HTML documents with non ASCII characters - steps 0, 1, 2, and 3.
- Presenting non ASCII characters in HTML documents - steps 4, 5, 6, and 7.
(Continued on next part...)
Part:
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