How to change the encoding inside the JDBC interface

Hi all,

I have a database which is EUC_TW encoded, but I would like to use
Big5 to encode my data.  I've tried serveral ways to program my
program, i.e. using string(in_bytestr, "BIG5") to convert my data.
However, the interface just use EUC_TW to store my data anyhow.

Any experience can share with  me?

Thanks 
Dave