org.apache.hadoop.mapred

类 FileSplit

java.lang.Object

org.apache.hadoop.mapreduce.InputSplit

org.apache.hadoop.mapred.FileSplit

所有已实现的接口:

Writable, InputSplit

public class FileSplit
extends InputSplit
implements InputSplit

A section of an input file. Returned by InputFormat.getSplits(JobConf, int) and passed to InputFormat.getRecordReader(InputSplit,JobConf,Reporter).

构造器概要

构造器

构造器和说明
FileSplit(Path file, long start, long length, JobConf conf) 已过时。
FileSplit(Path file, long start, long length, String[] hosts) Constructs a split with host information

方法概要

方法

限定符和类型	方法和说明
long	getLength() The number of bytes in the file to process.
String[]	getLocations() Get the list of nodes by name where the data for the split would be local.
Path	getPath() The file containing this split's data.
long	getStart() The position of the first byte in the file to process.
void	readFields(DataInput in) Deserialize the fields of this object from in.
String	toString()
void	write(DataOutput out) Serialize the fields of this object to out.

从类继承的方法 java.lang.Object

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

构造器详细资料

FileSplit

@Deprecated
public FileSplit(Path file,
                    long start,
                    long length,
                    JobConf conf)

已过时。

Constructs a split.

参数:

file - the file name

start - the position of the first byte in the file to process

length - the number of bytes in the file to process

FileSplit

public FileSplit(Path file,
         long start,
         long length,
         String[] hosts)

Constructs a split with host information

参数:

file - the file name

start - the position of the first byte in the file to process

length - the number of bytes in the file to process

hosts - the list of hosts containing the block, possibly null

方法详细资料

getPath

public Path getPath()

The file containing this split's data.

getStart

public long getStart()

The position of the first byte in the file to process.

getLength

public long getLength()

The number of bytes in the file to process.

指定者:

getLength 在接口中 InputSplit

指定者:

getLength 在类中 InputSplit

返回:

the number of bytes in the split

toString

public String toString()

覆盖:

toString 在类中 Object

write

public void write(DataOutput out)
           throws IOException

从接口复制的说明: Writable

Serialize the fields of this object to out.

指定者:

write 在接口中 Writable

参数:

out - DataOuput to serialize this object into.

抛出:

IOException

readFields

public void readFields(DataInput in)
                throws IOException

从接口复制的说明: Writable

Deserialize the fields of this object from in.

For efficiency, implementations should attempt to re-use storage in the existing object where possible.

指定者:

readFields 在接口中 Writable

参数:

in - DataInput to deseriablize this object from.

抛出:

IOException

getLocations

public String[] getLocations()
                      throws IOException

从类复制的说明: InputSplit

Get the list of nodes by name where the data for the split would be local. The locations do not need to be serialized.

指定者:

getLocations 在接口中 InputSplit

指定者:

getLocations 在类中 InputSplit

返回:

a new array of the node nodes.

抛出:

IOException