摘要： 该程序实现的是对指定文档中指定单词的词频进行计算 1 /** 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to yo... 阅读全文

摘要： 引用自Introduction to MapReduceMapReduce = functional programming meets distributed processing on steroidsDate back toLisp(in the 50's)Lisp:Focus on particular a dialect: “Scheme”Functions written in prefix notation(+ 1 2) -> 3(* 3 4) -> 12(sqrt (+ (* 3 3) (* 4 4))) -> 5(define x 3) -> 阅读全文