org.apache.hadoop.mapred

类 KeyValueLineRecordReader

java.lang.Object

org.apache.hadoop.mapred.KeyValueLineRecordReader

所有已实现的接口:

RecordReader<Text,Text>

public class KeyValueLineRecordReader
extends Object
implements RecordReader<Text,Text>

This class treats a line in the input as a key/value pair separated by a separator character. The separator can be specified in config file under the attribute name key.value.separator.in.input.line. The default separator is the tab character ('\t').

构造器概要

构造器

构造器和说明
KeyValueLineRecordReader(Configuration job, FileSplit split)

方法概要

方法

限定符和类型	方法和说明
void	close() Close this InputSplit to future operations.
Text	createKey() Create an object of the appropriate type to be used as a key.
Text	createValue() Create an object of the appropriate type to be used as a value.
static int	findSeparator(byte[] utf, int start, int length, byte sep)
Class	getKeyClass()
long	getPos() Returns the current position in the input.
float	getProgress() How much of the input has the RecordReader consumed i.e.
boolean	next(Text key, Text value) Read key/value pair in a line.

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

KeyValueLineRecordReader

public KeyValueLineRecordReader(Configuration job,
                        FileSplit split)
                         throws IOException

抛出:

IOException

方法详细资料

getKeyClass

public Class getKeyClass()

createKey

public Text createKey()

从接口复制的说明: RecordReader

Create an object of the appropriate type to be used as a key.

指定者:

createKey 在接口中 RecordReader<Text,Text>

返回:

a new key object.

createValue

public Text createValue()

从接口复制的说明: RecordReader

Create an object of the appropriate type to be used as a value.

指定者:

createValue 在接口中 RecordReader<Text,Text>

返回:

a new value object.

findSeparator

public static int findSeparator(byte[] utf,
                int start,
                int length,
                byte sep)

next

public boolean next(Text key,
           Text value)
             throws IOException

Read key/value pair in a line.

指定者:

next 在接口中 RecordReader<Text,Text>

参数:

key - the key to read data into

value - the value to read data into

返回:

true iff a key/value was read, false if at EOF

抛出:

IOException

getProgress

public float getProgress()
                  throws IOException

从接口复制的说明: RecordReader

How much of the input has the RecordReader consumed i.e. has been processed by?

指定者:

getProgress 在接口中 RecordReader<Text,Text>

返回:

progress from 0.0 to 1.0.

抛出:

IOException

getPos

public long getPos()
            throws IOException

从接口复制的说明: RecordReader

Returns the current position in the input.

指定者:

getPos 在接口中 RecordReader<Text,Text>

返回:

the current position in the input.

抛出:

IOException

close

public void close()
           throws IOException

从接口复制的说明: RecordReader

Close this InputSplit to future operations.

指定者:

close 在接口中 RecordReader<Text,Text>

抛出:

IOException