org.apache.hadoop.tools.distcp2

类 DistCp

java.lang.Object

org.apache.hadoop.conf.Configured

org.apache.hadoop.tools.distcp2.DistCp

所有已实现的接口:

Configurable, Tool

public class DistCp
extends Configured
implements Tool

DistCp is the main driver-class for DistCpV2. For command-line use, DistCp::main() orchestrates the parsing of command-line parameters and the launch of the DistCp job. For programmatic use, a DistCp object can be constructed by specifying options (in a DistCpOptions object), and DistCp::execute() may be used to launch the copy-job. DistCp may alternatively be sub-classed to fine-tune behaviour.

字段概要

字段

限定符和类型	字段和说明
static Random	rand

构造器概要

构造器

构造器和说明
DistCp(Configuration configuration, DistCpOptions inputOptions) Public Constructor.

方法概要

方法

限定符和类型	方法和说明
protected Path	createInputFileListing(Job job) Create input listing by invoking an appropriate copy listing implementation.
Job	execute() Implements the core-execution.
protected Path	getFileListingPath() Get default name of the copy listing file.
static void	main(String[] argv) Main function of the DistCp program.
int	run(String[] argv) Implementation of Tool::run().

从类继承的方法 org.apache.hadoop.conf.Configured

getConf, setConf

从类继承的方法 java.lang.Object

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

从接口继承的方法 org.apache.hadoop.conf.Configurable

getConf, setConf

字段详细资料

rand

public static final Random rand

构造器详细资料

DistCp

public DistCp(Configuration configuration,
      DistCpOptions inputOptions)
       throws Exception

Public Constructor. Creates DistCp object with specified input-parameters. (E.g. source-paths, target-location, etc.)

参数:

inputOptions - Options (indicating source-paths, target-location.)

configuration - The Hadoop configuration against which the Copy-mapper must run.

抛出:

Exception, - on failure.

Exception

方法详细资料

run

public int run(String[] argv)

Implementation of Tool::run(). Orchestrates the copy of source file(s) to target location, by: 1. Creating a list of files to be copied to target. 2. Launching a Map-only job to copy the files. (Delegates to execute().)

指定者:

run 在接口中 Tool

参数:

argv - List of arguments passed to DistCp, from the ToolRunner.

返回:

On success, it returns 0. Else, -1.

execute

public Job execute()
            throws Exception

Implements the core-execution. Creates the file-list for copy, and launches the Hadoop-job, to do the copy.

返回:

Job handle

抛出:

Exception, - on failure.

Exception

createInputFileListing

protected Path createInputFileListing(Job job)
                               throws IOException

Create input listing by invoking an appropriate copy listing implementation. Also add delegation tokens for each path to job's credential store

参数:

job - - Handle to job

返回:

Returns the path where the copy listing is created

抛出:

IOException - - If any

getFileListingPath

protected Path getFileListingPath()
                           throws IOException

Get default name of the copy listing file. Use the meta folder to create the copy listing file

返回:

- Path where the copy listing file has to be saved

抛出:

IOException - - Exception if any

main

public static void main(String[] argv)

Main function of the DistCp program. Parses the input arguments (via OptionsParser), and invokes the DistCp::run() method, via the ToolRunner.

参数:

argv - Command-line arguments sent to DistCp.