类 org.apache.hadoop.mapred.join.CompositeRecordReader
的使用

使用CompositeRecordReader的程序包

程序包	说明
org.apache.hadoop.mapred.join	Given a set of sorted datasets keyed with the same class and yielding equal partitions, it is possible to effect a join of those datasets prior to the map.

org.apache.hadoop.mapred.join中CompositeRecordReader的使用

org.apache.hadoop.mapred.join中CompositeRecordReader的子类

限定符和类型	类和说明
class	InnerJoinRecordReader<K extends WritableComparable> Full inner join.
class	JoinRecordReader<K extends WritableComparable> Base class for Composite joins returning Tuples of arbitrary Writables.
class	MultiFilterRecordReader<K extends WritableComparable,V extends Writable> Base class for Composite join returning values derived from multiple sources, but generally not tuples.
class	OuterJoinRecordReader<K extends WritableComparable> Full outer join.
class	OverrideRecordReader<K extends WritableComparable,V extends Writable> Prefer the "rightmost" data source for this key.