问题描述
为什么有两个独立的包的map-reduce Apache的Hadoop的包树包:
Why are there two separate packages map-reduce package in Apache's hadoop package tree:
org.apache.hadoop.mapred
<一个href=\"http://javasource$c$c.org/html/open-source/hadoop/hadoop-1.0.3/org/apache/hadoop/ma$p$pd/\">http://javasource$c$c.org/html/open-source/hadoop/hadoop-1.0.3/org/apache/hadoop/ma$p$pd/
org.apache.hadoop.mapreduce
<一个href=\"http://javasource$c$c.org/html/open-source/hadoop/hadoop-1.0.3/org/apache/hadoop/ma$p$pduce/\">http://javasource$c$c.org/html/open-source/hadoop/hadoop-1.0.3/org/apache/hadoop/ma$p$pduce/
他们为什么要分离出来?是否有明确本文档?
Why are they separated out? Is there documentation that clarifies this?
推荐答案
他们被分离出来,因为这两个包的重新present两种不同的API。 org.apache.hadoop.ma preD
是旧的API和 org.apache.hadoop.ma preduce
是新的。事情就这样让程序员编写马preduce作业更方便,更轻松,精致时尚。您可能会发现此有用的,其中谈到了详细差异。
They are separated out because both of these packages represent 2 different APIs. org.apache.hadoop.mapred
is the older API and org.apache.hadoop.mapreduce
is the new one. And it was done to allow programmers write MapReduce jobs in a more convenient, easier and sophisticated fashion. You might find this presentation useful, which talks about the differences in detail.
希望这回答了你的问题。
Hope this answers your question.
这篇关于hadoop.ma preD VS hadoop.ma preduce?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!