This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Try 'smsniff' (google it); it sniffs all tcp conversations taking place from your windows machine and presents them in a neat UI. Have never tried it for JDBC though; but it does give size information.