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.
In Struts you do this with a combination of the <html:file> tag and a property of type FormFile in your Actionform bean. The best way to learn how to do it is by examining the upload example in the examples war file that comes with the Struts download.