## 在线练习 [http://cloudcomputing.ruc.edu.cn](http://cloudcomputing.ruc.edu.cn) ## 处理 1. select：直接分析输入数据，取出需要的字段数据即可 1. where: 也是对输入数据处理的过程中进行处理，判断是否需要该数据 1. aggregation:min, max, sum 1. group by: 通过Reducer实现 1. sort 1. join: map join, reduce join ## Third-Party Libraries export LIBJARS=$MYLIB/commons-lang-2.3.jar, hadoop jar prohadoop-0.0.1-SNAPSHOT.jar org.aspress.prohadoop.c3. WordCountUsingToolRunner -libjars $LIBJARS hadoop jar prohadoop-0.0.1-SNAPSHOT-jar-with-dependencies.jar org.aspress.prohadoop.c3. WordCountUsingToolRunner The dependent libraries are now included inside the application JAR file 一般还是上面的好，指定依赖可以利用Public Cache，如果是包含依赖，则每次都需要拷贝 ## 参考书籍 [MapReduce Design Patterns](http://book.douban.com/subject/11229683/)