程序包 org.apache.hadoop.mapred.lib

Library of generally useful mappers, reducers, and partitioners.

请参阅: 说明

接口概要

接口	说明
InputSampler.Sampler<K,V>	Interface to sample using an InputFormat.

类概要

类	说明
BinaryPartitioner<V>	Partition BinaryComparable keys using a configurable part of the bytes array returned by BinaryComparable.getBytes().
ChainMapper	The ChainMapper class allows to use multiple Mapper classes within a single Map task.
ChainReducer	The ChainReducer class allows to chain multiple Mapper classes after a Reducer within the Reducer task.
CombineFileInputFormat<K,V>	An abstract InputFormat that returns CombineFileSplit's in InputFormat.getSplits(JobConf, int) method.
CombineFileRecordReader<K,V>	A generic RecordReader that can hand out different recordReaders for each chunk in a CombineFileSplit.
CombineFileSplit	A sub-collection of input files.
DelegatingInputFormat<K,V>	An InputFormat that delegates behaviour of paths to multiple other InputFormats.
DelegatingMapper<K1,V1,K2,V2>	An Mapper that delegates behaviour of paths to multiple other mappers.
FieldSelectionMapReduce<K,V>	This class implements a mapper/reducer class that can be used to perform field selections in a manner similar to unix cut.
HashPartitioner<K2,V2>	Partition keys by their Object.hashCode().
IdentityMapper<K,V>	Implements the identity function, mapping inputs directly to outputs.
IdentityReducer<K,V>	Performs no reduction, writing all input values directly to the output.
InputSampler<K,V>	Utility for collecting samples and writing a partition file for TotalOrderPartitioner.
InputSampler.IntervalSampler<K,V>	Sample from s splits at regular intervals.
InputSampler.RandomSampler<K,V>	Sample from random points in the input.
InputSampler.SplitSampler<K,V>	Samples the first n records from s splits.
InverseMapper<K,V>	A Mapper that swaps keys and values.
KeyFieldBasedComparator<K,V>	This comparator implementation provides a subset of the features provided by the Unix/GNU Sort.
KeyFieldBasedPartitioner<K2,V2>	Defines a way to partition keys based on certain key fields (also see KeyFieldBasedComparator.
LongSumReducer<K>	A Reducer that sums long values.
MultipleInputs	This class supports MapReduce jobs that have multiple input paths with a different InputFormat and Mapper for each path
MultipleOutputFormat<K,V>	This abstract class extends the FileOutputFormat, allowing to write the output data to different output files.
MultipleOutputs	The MultipleOutputs class simplifies writting to additional outputs other than the job default output via the OutputCollector passed to the map() and reduce() methods of the Mapper and Reducer implementations.
MultipleSequenceFileOutputFormat<K,V>	This class extends the MultipleOutputFormat, allowing to write the output data to different output files in sequence file output format.
MultipleTextOutputFormat<K,V>	This class extends the MultipleOutputFormat, allowing to write the output data to different output files in Text output format.
MultithreadedMapRunner<K1,V1,K2,V2>	Multithreaded implementation for @link org.apache.hadoop.mapred.MapRunnable.
NLineInputFormat	NLineInputFormat which splits N lines of input as one split.
NullOutputFormat<K,V>	Consume all outputs and put them in /dev/null.
RegexMapper<K>	A Mapper that extracts text matching a regular expression.
TokenCountMapper<K>	A Mapper that maps text values into pairs.
TotalOrderPartitioner<K extends WritableComparable,V>	Partitioner effecting a total order by reading split points from an externally generated source.

程序包org.apache.hadoop.mapred.lib的说明

Library of generally useful mappers, reducers, and partitioners.