http://jingyan.baidu.com/article/e75057f2c030ecebc91a89af.html
http://www.tuicool.com/articles/BzI3UfZ
小例子http://m.blog.csdn.net/article/details?id=53427290 词频统计
http://www.cnblogs.com/shishanyuan/p/4747778.html
http://blog.csdn.net/shifenglov/article/details/43795597 电影评分协同过滤
