mongodb mapReduce

mongodb mapReduce参考

http://blog.csdn.net/q383965374/article/details/8510030

MongoDB JAVA-API执行mapreduce的几种方法
http://my.oschina.net/huzorro/blog/75210

MongoDB 使用mapreduce完成数据迭代
http://my.oschina.net/huzorro/blog/75060

介绍一下MapReduce工作原理
http://blog.csdn.net/opennaive/article/details/7514146

mapReduce(聚合函数)
http://www.infoq.com/cn/articles/implementing-aggregation-functions-in-mongodb