I checked the second website you mentioned in your question: onbarcode.com. It seems that you go to the wrong place. I find this on that website, http://www.onbarcode.com/ireport/ I think this is what you really want, not Jasper
Check this post:http://community.jaspersoft.com/questions/540153/how-create-qrcode-ireport and this website:http://www.onbarcode.com/ireport/ It describes in detail.