for /F "tokens=2,3,4 delims=/ " %%d in ('date /T') do ( 
set jour=%%d%%e%%f
)
set DB_USERNAME=SYSTEM
set DB_PASSWORD=SYSTEMADMIN
set TNS_ALIAS=test
set DUMPFILE=F:\temp\%JOUR%_FULL_EXPORT_%TNS_ALIAS%.dmp

echo userid=%DB_USERNAME%/%DB_PASSWORD%@%TNS_ALIAS% >F:\temp\EXP.PAR
echo file=%DUMPFILE% >>F:\temp\EXP.PAR
echo log=F:\temp\%JOUR%_FULL_EXPORT_%TNS_ALIAS%.LOG >> F:\temp\EXP.PAR
echo full=y >>F:\temp\EXP.PAR

E:\oracle\product\10.2.0\db_1\BIN\EXP PARFILE=F:\temp\EXP.PAR