程序包 org.apache.hadoop.hdfs.protocol

接口概要

接口	说明
ClientDatanodeProtocol	An client-datanode protocol for block recovery
ClientProtocol	ClientProtocol is used by user code via DistributedFileSystem class to communicate with the NameNode.
DataTransferProtocol	The Client transfers data to/from datanode using a streaming protocol.
FSConstants	Some handy constants

类概要

类	说明
Block	A Block is a Hadoop FS primitive, identified by a long.
BlockListAsLongs	This class provides an interface for accessing list of blocks that has been implemented as long[].
BlockLocalPathInfo	A block and the full path information to the block data file and the metadata file stored on the local file system.
DatanodeID	DatanodeID is composed of the data node name (hostname:portNumber) and the data storage ID, which it currently represents.
DatanodeInfo	DatanodeInfo represents the status of a DataNode.
DataTransferProtocol.PipelineAck	reply
DirectoryListing	This class defines a partial listing of a directory to support iterative directory listing.
HdfsFileStatus	Interface that represents the over the wire information for a file.
LayoutVersion	This class tracks changes in the layout version of HDFS.
LocatedBlock	A LocatedBlock is a pair of Block, DatanodeInfo[] objects.
LocatedBlocks	Collection of blocks with their locations and the file length.

枚举概要

枚举	说明
DatanodeInfo.AdminStates
FSConstants.DatanodeReportType
FSConstants.SafeModeAction
FSConstants.UpgradeAction	Distributed upgrade actions: 1.
LayoutVersion.Feature	Enums for features that change the layout version.

异常错误概要

异常错误	说明
AlreadyBeingCreatedException	The exception that happens when you ask to create a file that already is being created, but is not closed yet.
DSQuotaExceededException
NSQuotaExceededException
QuotaExceededException	This exception is thrown when modification to HDFS results in violation of a directory quota.
UnregisteredDatanodeException	This exception is thrown when a datanode that has not previously registered is trying to access the name node.