jfreechart初学入门的几篇好文章

jfreechart初学入门的几篇好文章：
http://www.blogjava.net/amigoxie/archive/2007/09/30/149765.html
http://www.blogjava.net/JavaExplore/archive/2006/09/01/67217.html
http://www.blogjava.net/JavaExplore/archive/2006/09/12/69261.html