Hadoop 源码详解之RecordReader接口
Hadoop 源码详解之RecordReader接口
1. 类释义
RecordReader reads <key, value> pairs from an InputSplit.
RecordReader从InputSplit中读取<key,value> pairs 。
RecordReader, typically, converts the byte-oriented view of the input, provided by the InputSplit, and presents a record-oriented view for the Mapper and Reducer tasks for processing. It thus assumes the responsibility of processing record boundaries and presenting the tasks with keys and values.
RecordReader转换输入面向字节的视图，由InputSplit提供，并且展示一个面向记录的视图给Mapper以及Reducer任务从而进行处理。它承担处理记录边界并且使用keys 和 values展示任务的责任。
2. 源码
@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class RecordReader<KEYIN, VALUEIN> implements Closeable {
...
}