org.apache.hadoop.mapred.lib

类 HashPartitioner<K2,V2>

java.lang.Object

org.apache.hadoop.mapred.lib.HashPartitioner<K2,V2>

所有已实现的接口:

JobConfigurable, Partitioner<K2,V2>

public class HashPartitioner<K2,V2>
extends Object
implements Partitioner<K2,V2>

Partition keys by their Object.hashCode().

构造器概要

构造器

构造器和说明
HashPartitioner()

方法概要

方法

限定符和类型	方法和说明
void	configure(JobConf job) Initializes a new instance from a JobConf.
int	getPartition(K2 key, V2 value, int numReduceTasks) Use Object.hashCode() to partition.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

HashPartitioner

public HashPartitioner()

方法详细资料

configure

public void configure(JobConf job)

从接口复制的说明: JobConfigurable

Initializes a new instance from a JobConf.

指定者:

configure 在接口中 JobConfigurable

参数:

job - the configuration

getPartition

public int getPartition(K2 key,
               V2 value,
               int numReduceTasks)

Use Object.hashCode() to partition.

指定者:

getPartition 在接口中 Partitioner<K2,V2>

参数:

key - the key to be paritioned.

value - the entry value.

numReduceTasks - the total number of partitions.

返回:

the partition number for the key.