http://blog.csdn.net/c4501srsy/article/details/17403927
http://blog.csdn.net/yy649487394/article/details/45075167
http://jingyan.baidu.com/article/b7001fe199dbf00e7382dd75.html?qq-pf-to=pcqq.c2c
http://blog.csdn.net/kangxidashen/article/details/23472073
http://www.cnblogs.com/qwcbeyond/archive/2011/04/05/2005531.html