开发者学堂课程【Hadoop 分布式计算框架 MapReduce：序列化案例 Mapper】学习笔记，与课程紧密联系，让用户快速学习知识。

课程地址：https://developer.aliyun.com/learning/course/94/detail/1493

​序列化案例 Mapper

1. 获取一行

2. 切割 \t

3. 封装对象

4. 写出

 

1.获取一行

​String line = value. toString ();​

2. 切割\t

​String[] fields = line. split("\t");​

3.封装对象

​k.set(fields[1]);//封装手机号​

​long upFlow = Long. parseLong (fields [fields. length- 3]);long downFlow = Long. parseLong (fields [fields. length- 2);​

​v.setUpFlow(upFlow);​

v.setDownFlow(downFlow);

//v.set(upFlow,downFlow);

4.写出

context. write (k, v);