org.apache.hadoop.hive.serde2

Class JsonSerDe

java.lang.Object

org.apache.hadoop.hive.serde2.AbstractSerDe

org.apache.hadoop.hive.serde2.JsonSerDe

All Implemented Interfaces:

Deserializer, SerDe, Serializer

public class JsonSerDe
extends AbstractSerDe

Hive SerDe for processing JSON formatted data. This is typically paired with the TextInputFormat and therefore each line provided to this SerDe must be a single, and complete JSON object.

Example

{"name="john","age"=30}
{"name="sue","age"=32}

Field Summary

Fields

Modifier and Type	Field and Description
static String	BINARY_FORMAT
static String	IGNORE_EXTRA
static String	NULL_EMPTY_LINES
static String	STRINGIFY_COMPLEX

Fields inherited from class org.apache.hadoop.hive.serde2.AbstractSerDe

configuration, log, partitionProperties, properties, tableProperties

Constructor Summary

Constructors

Constructor and Description
JsonSerDe()

Method Summary

Modifier and Type	Method and Description
Object	deserialize(org.apache.hadoop.io.Writable blob) Deserialize an object out of a Writable blob containing JSON text.
BinaryEncoding	getBinaryEncoding()
ObjectInspector	getObjectInspector() Returns an object inspector for the specified schema that is capable of reading in the object representation of the JSON string.
Class<? extends org.apache.hadoop.io.Writable>	getSerializedClass() Returns the Writable class that would be returned by the serialize method.
StructTypeInfo	getTypeInfo()
void	initialize(org.apache.hadoop.conf.Configuration configuration, Properties tableProperties, Properties partitionProperties) Initialize the SerDe.
void	initialize(org.apache.hadoop.conf.Configuration configuration, Properties tableProperties, Properties partitionProperties, boolean writeablePrimitivesDeserialize) Initialize the SerDe.
boolean	isNullEmptyLines()
org.apache.hadoop.io.Writable	serialize(Object obj, ObjectInspector objInspector) Given an object and object inspector pair, traverse the object and generate a Text representation of the object.

Methods inherited from class org.apache.hadoop.hive.serde2.AbstractSerDe

getColumnComments, getColumnNames, getColumnTypes, getConfiguration, getPartitionColumnComments, getPartitionColumnNames, getPartitionColumnTypes, getSerDeStats, parseColumnComments, parseColumnNames, parseColumnNames, parseColumnTypes, parseColumnTypes, shouldStoreFieldsInMetastore, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.hive.serde2.SerDe

handleJobLevelConfiguration

Field Detail

BINARY_FORMAT

public static final String BINARY_FORMAT

See Also:

Constant Field Values

STRINGIFY_COMPLEX

public static final String STRINGIFY_COMPLEX

See Also:

Constant Field Values

IGNORE_EXTRA

public static final String IGNORE_EXTRA

See Also:

Constant Field Values

NULL_EMPTY_LINES

public static final String NULL_EMPTY_LINES

See Also:

Constant Field Values

Constructor Detail

JsonSerDe

public JsonSerDe()

Method Detail

initialize

public void initialize(org.apache.hadoop.conf.Configuration configuration,
                       Properties tableProperties,
                       Properties partitionProperties)
                throws SerDeException

Initialize the SerDe. By default, items being deserialized are expected to be wrapped in Hadoop Writable objects and objects being serialized are expected to be Java primitive objects.

Overrides:

initialize in class AbstractSerDe

Parameters:

configuration - Hadoop configuration

tableProperties - Table properties

partitionProperties - Partition properties (may be null if table has no partitions)

Throws:

NullPointerException - if tableProperties is null

SerDeException - if SerDe fails to initialize

initialize

public void initialize(org.apache.hadoop.conf.Configuration configuration,
                       Properties tableProperties,
                       Properties partitionProperties,
                       boolean writeablePrimitivesDeserialize)
                throws SerDeException

Initialize the SerDe.

Parameters:

configuration - Hadoop configuration

tableProperties - Table properties

partitionProperties - Partition properties (may be null if table has no partitions)

writeablePrimitivesDeserialize - true if outputs are Hadoop Writable

Throws:

NullPointerException - if tableProperties is null

SerDeException - if SerDe fails to initialize

deserialize

public Object deserialize(org.apache.hadoop.io.Writable blob)
                   throws SerDeException

Deserialize an object out of a Writable blob containing JSON text. The return value of this function will be constant since the function will reuse the returned object. If the client wants to keep a copy of the object, the client needs to clone the returned value by calling ObjectInspectorUtils.getStandardObject().

Specified by:

deserialize in interface Deserializer

Overrides:

deserialize in class AbstractSerDe

Parameters:

blob - The Writable (Text) object containing a serialized object

Returns:

A List containing all the values of the row

Throws:

SerDeException

serialize

public org.apache.hadoop.io.Writable serialize(Object obj,
                                               ObjectInspector objInspector)
                                        throws SerDeException

Given an object and object inspector pair, traverse the object and generate a Text representation of the object.

Specified by:

serialize in interface Serializer

Overrides:

serialize in class AbstractSerDe

Throws:

SerDeException

getObjectInspector

public ObjectInspector getObjectInspector()
                                   throws SerDeException

Returns an object inspector for the specified schema that is capable of reading in the object representation of the JSON string.

Throws:

SerDeException

getSerializedClass

public Class<? extends org.apache.hadoop.io.Writable> getSerializedClass()

Description copied from class: AbstractSerDe

Returns the Writable class that would be returned by the serialize method. This is used to initialize SequenceFile header.

Specified by:

getSerializedClass in interface Serializer

Specified by:

getSerializedClass in class AbstractSerDe

getTypeInfo

public StructTypeInfo getTypeInfo()

getBinaryEncoding

public BinaryEncoding getBinaryEncoding()

isNullEmptyLines

public boolean isNullEmptyLines()