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Understanding Character Encoding in a Typical Java Web Application

Some pseudo codes:

String a = "A bunch of text"; //UTF-16
saveTextInDb(a); //Write to Oracle VARCHAR(15) column
String b = readTextFromDb(); //UTF-16
out.write(b); //Write to http response

When you save Java String(UTF-16) to Oracle VARCHAR (15), does Oracle also save this as UTF-16? Does Oracle VARCHAR length mean number of Unicode characters (not number of bytes)?

When we write bto ServletResponse, is it written as UTF-16 or are we by default converted to another encoding such as UTF-8?

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response.setEncoding("UTF-8");
Writer out = response.getWriter();

Writer, UTF-8. , :

Writer fileout = new OutputStreamWriter(new FileOutputStream(myfile), "ISO8859-1");

, .

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Oracle ( ) ( ). AL32UTF8 CHAR ( VARCHAR/VARCHAR2), Unicode, , , AL16UTF16/AL32UTF32.

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ServletResponse ISO 8859-1 ( 1) . UTF-8 , HTTP, Unicode, .

According to this document, Oracle can support UTF-8 or UTF-16 in the database. Your Oracle read / write methods will need to use the appropriate encoding appropriate to the database setup and translate it to / from the internal Java view.

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