引用
https://docs.google.com/document/d/1qxWPR9GbP2PI4WzBCAdl8dgOEo4-r_IEd34re5e6Ki4/edit
https://databricks-training.s3.amazonaws.com/movie-recommendation-with-mllib.html https://www.codementor.io/spark/tutorial/building-a-recommender-with-apache-spark-python-example-app-part1
http://blog.untrod.com/2016/06/simple-similar-products-recommendation-engine-in-python.html