http://www.cnblogs.com/tolimit/p/4551428.html
http://blog.163.com/liuqiang_mail@126/blog/static/1099688752012419602746/
http://blog.csdn.net/longyue0917/article/details/7420779
http://www.cnblogs.com/lcnewstart/archive/2010/12/08/1900369.html
