http://www.cnblogs.com/OceanDeep/archive/2011/10/14/2284574.html
http://www.cnblogs.com/fgficebear/archive/2009/08/25/1527417.html
http://www.cnblogs.com/OceanDeep/archive/2011/10/14/2284574.html
http://www.cnblogs.com/fgficebear/archive/2009/08/25/1527417.html