org.apache.hadoop.mapreduce.lib.input

类 KeyValueLineRecordReader

java.lang.Object

org.apache.hadoop.mapreduce.RecordReader<Text,Text>

org.apache.hadoop.mapreduce.lib.input.KeyValueLineRecordReader

所有已实现的接口:

Closeable, AutoCloseable

@InterfaceAudience.Public
@InterfaceStability.Stable
public class KeyValueLineRecordReader
extends 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 mapreduce.input.keyvaluelinerecordreader.key.value.separator. The default separator is the tab character ('\t').

字段概要

字段

限定符和类型	字段和说明
static String	KEY_VALUE_SEPERATOR

构造器概要

构造器

构造器和说明
KeyValueLineRecordReader(Configuration conf)

方法概要

方法

限定符和类型	方法和说明
void	close() Close the record reader.
static int	findSeparator(byte[] utf, int start, int length, byte sep)
Text	getCurrentKey() Get the current key
Text	getCurrentValue() Get the current value.
Class	getKeyClass()
float	getProgress() The current progress of the record reader through its data.
void	initialize(InputSplit genericSplit, TaskAttemptContext context) Called once at initialization.
boolean	nextKeyValue() Read key/value pair in a line.
static void	setKeyValue(Text key, Text value, byte[] line, int lineLen, int pos)

从类继承的方法 java.lang.Object

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

字段详细资料

KEY_VALUE_SEPERATOR

public static final String KEY_VALUE_SEPERATOR

另请参阅:

常量字段值

构造器详细资料

KeyValueLineRecordReader

public KeyValueLineRecordReader(Configuration conf)
                         throws IOException

抛出:

IOException

方法详细资料

getKeyClass

public Class getKeyClass()

initialize

public void initialize(InputSplit genericSplit,
              TaskAttemptContext context)
                throws IOException

从类复制的说明: RecordReader

Called once at initialization.

指定者:

initialize 在类中 RecordReader<Text,Text>

参数:

genericSplit - the split that defines the range of records to read

context - the information about the task

抛出:

IOException

findSeparator

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

setKeyValue

public static void setKeyValue(Text key,
               Text value,
               byte[] line,
               int lineLen,
               int pos)

nextKeyValue

public boolean nextKeyValue()
                     throws IOException

Read key/value pair in a line.

指定者:

nextKeyValue 在类中 RecordReader<Text,Text>

返回:

true if a key/value pair was read

抛出:

IOException

getCurrentKey

public Text getCurrentKey()

从类复制的说明: RecordReader

Get the current key

指定者:

getCurrentKey 在类中 RecordReader<Text,Text>

返回:

the current key or null if there is no current key

getCurrentValue

public Text getCurrentValue()

从类复制的说明: RecordReader

Get the current value.

指定者:

getCurrentValue 在类中 RecordReader<Text,Text>

返回:

the object that was read

getProgress

public float getProgress()
                  throws IOException

从类复制的说明: RecordReader

The current progress of the record reader through its data.

指定者:

getProgress 在类中 RecordReader<Text,Text>

返回:

a number between 0.0 and 1.0 that is the fraction of the data read

抛出:

IOException

close

public void close()
           throws IOException

从类复制的说明: RecordReader

Close the record reader.

指定者:

close 在接口中 Closeable

指定者:

close 在接口中 AutoCloseable

指定者:

close 在类中 RecordReader<Text,Text>

抛出:

IOException