类 org.apache.hadoop.mapred.MapReduceBase
的使用

使用MapReduceBase的程序包

程序包	说明
org.apache.hadoop.contrib.index.mapred
org.apache.hadoop.examples	Hadoop example code.
org.apache.hadoop.examples.dancing	This package is a distributed implementation of Knuth's dancing links algorithm that can run under Hadoop.
org.apache.hadoop.examples.terasort	This package consists of 3 map/reduce applications for Hadoop to compete in the annual terabyte sort competition.
org.apache.hadoop.mapred.lib	Library of generally useful mappers, reducers, and partitioners.
org.apache.hadoop.tools

org.apache.hadoop.contrib.index.mapred中MapReduceBase的使用

org.apache.hadoop.contrib.index.mapred中MapReduceBase的子类

限定符和类型	类和说明
class	IndexUpdateCombiner This combiner combines multiple intermediate forms into one intermediate form.
class	IndexUpdateMapper<K extends WritableComparable,V extends Writable> This class applies local analysis on a key-value pair and then convert the result docid-operation pair to a shard-and-intermediate form pair.
class	IndexUpdateReducer This reducer applies to a shard the changes for it.

org.apache.hadoop.examples中MapReduceBase的使用

org.apache.hadoop.examples中MapReduceBase的子类

限定符和类型	类和说明
static class	MultiFileWordCount.MapClass This Mapper is similar to the one in WordCount.MapClass.
static class	PiEstimator.PiMapper Mapper class for Pi estimation.
static class	PiEstimator.PiReducer Reducer class for Pi estimation.

org.apache.hadoop.examples.dancing中MapReduceBase的使用

org.apache.hadoop.examples.dancing中MapReduceBase的子类

限定符和类型	类和说明
static class	DistributedPentomino.PentMap Each map takes a line, which represents a prefix move and finds all of the solutions that start with that prefix.

org.apache.hadoop.examples.terasort中MapReduceBase的使用

org.apache.hadoop.examples.terasort中MapReduceBase的子类

限定符和类型	类和说明
static class	TeraGen.SortGenMapper The Mapper class that given a row number, will generate the appropriate output line.

org.apache.hadoop.mapred.lib中MapReduceBase的使用

org.apache.hadoop.mapred.lib中MapReduceBase的子类

限定符和类型	类和说明
class	IdentityMapper<K,V> Implements the identity function, mapping inputs directly to outputs.
class	IdentityReducer<K,V> Performs no reduction, writing all input values directly to the output.
class	InverseMapper<K,V> A Mapper that swaps keys and values.
class	LongSumReducer<K> A Reducer that sums long values.
class	RegexMapper<K> A Mapper that extracts text matching a regular expression.
class	TokenCountMapper<K> A Mapper that maps text values into pairs.

org.apache.hadoop.tools中MapReduceBase的使用

org.apache.hadoop.tools中MapReduceBase的子类

限定符和类型	类和说明
static class	Logalyzer.LogRegexMapper<K extends WritableComparable> A Mapper that extracts text matching a regular expression.