JSONReader.Feature

java.lang.Object
- java.lang.Enum<JSONReader.Feature>
- - com.alibaba.fastjson2.JSONReader.Feature

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<JSONReader.Feature>

Enclosing class:

JSONReader
```
public static enum JSONReader.Feature
extends java.lang.Enum<JSONReader.Feature>
```
Feature is used to control the behavior of JSON reading and parsing in FASTJSON2. Each feature represents a specific configuration option that can be enabled or disabled to customize how JSON data is processed during deserialization.
Features can be enabled in several ways:
- Using factory methods like JSONReader.of(String, Context) with JSONFactory.createReadContext(JSONReader.Feature...)
- Using Context#config(Feature...) method
- Using JSONFactory.getDefaultReaderFeatures() for global configuration
Example usage:
```
 // Enable FieldBased feature for this reader only
 try (JSONReader reader = JSONReader.of(json, JSONReader.Feature.FieldBased)) {
     MyObject obj = reader.read(MyObject.class);
 }

 // Enable multiple features
 try (JSONReader reader = JSONReader.of(json,
         JSONReader.Feature.FieldBased,
         JSONReader.Feature.TrimString)) {
     MyObject obj = reader.read(MyObject.class);
 }

 // Using context configuration
 JSONReader.Context context = new JSONReader.Context();
 context.config(JSONReader.Feature.FieldBased);
 try (JSONReader reader = JSONReader.of(json, context)) {
     MyObject obj = reader.read(MyObject.class);
 }
 
```
Features are implemented as bitmask flags for efficient storage and checking. Each feature has a unique mask value that is used internally to determine whether the feature is enabled in a given configuration.
Since:

2.0.0

See Also:

JSONReader.Context, JSONFactory

Enum Constant Summary

Enum Constants
Enum Constant and Description
`AllowUnQuotedFieldNames` Feature that determines whether to allow unquoted field names in JSON.
`Base64StringAsByteArray` Feature that determines whether to treat Base64-encoded strings as byte arrays during deserialization.
`DisableReferenceDetect` Feature that disables reference detection during deserialization.
`DisableSingleQuote` Feature that disables the support for single quote.
`DisableStringArrayUnwrapping` Feature that disables unwrapping of single-element string arrays to scalar values.
`DuplicateKeyValueAsArray` Feature that determines how to handle duplicate keys in JSON objects.
`EmptyStringAsNull` Feature that determines whether to convert empty strings to null values during deserialization.
`ErrorOnEnumNotMatch` Feature that determines whether to throw an exception when an enum value in JSON does not match any of the defined enum constants.
`ErrorOnNoneSerializable` Feature that determines whether to throw an exception when encountering non-serializable classes during deserialization.
`ErrorOnNotSupportAutoType` Feature that determines whether to throw an exception when autoType is not supported.
`ErrorOnNullForPrimitives` Feature that determines whether to throw an exception when null values are encountered for primitive types during deserialization.
`ErrorOnUnknownProperties` Feature that determines whether to throw an exception when unknown properties are encountered during deserialization.
`FieldBased` Feature that determines whether to use field-based deserialization instead of getter/setter-based deserialization.
`IgnoreAutoTypeNotMatch` Feature that determines whether to ignore autoType mismatches during deserialization.
`IgnoreCheckClose` Feature that determines whether to ignore checking for resource cleanup.
`IgnoreNoneSerializable` Feature that determines whether to ignore non-serializable classes during deserialization.
`IgnoreNullPropertyValue` Feature that determines whether to ignore null property values during deserialization.
`IgnoreSetNullValue` Feature that determines whether to ignore null values when setting properties.
`InitStringFieldAsEmpty` Feature that determines whether to initialize string fields as empty strings instead of null values.
`NonErrorOnNumberOverflow` Feature that determines whether to avoid throwing exceptions on number overflow during deserialization.
`NonStringKeyAsString` Feature that determines whether to treat non-string keys as strings during deserialization.
`NonZeroNumberCastToBooleanAsTrue` Feature that determines whether to cast non-zero numbers to boolean true during deserialization.
`NullOnError` Feature that determines whether to return null on error during deserialization.
`SupportArrayToBean` Feature that determines whether to support deserializing JSON arrays into Java beans.
`SupportAutoType` Deprecated. It is not safe to explicitly turn on autoType, it is recommended to use AutoTypeBeforeHandler
`SupportClassForName` Feature that enables support for Class.forName() during deserialization.
`SupportSmartMatch` Feature that enables smart matching of field names during deserialization.
`TrimString` Feature that determines whether to trim whitespace from string values during deserialization.
`UseBigDecimalForDoubles` Feature that determines whether to deserialize floating-point numbers as BigDecimal when the target type is double.
`UseBigDecimalForFloats` Feature that determines whether to deserialize floating-point numbers as BigDecimal when the target type is float.
`UseBigIntegerForInts` Feature that determines whether JSON integral (non-floating-point) numbers are to be deserialized into `BigInteger`s if only generic type description (either `Object` or `Number`, or within untyped `Map` or `Collection` context) is available.
`UseDefaultConstructorAsPossible` Feature that determines whether to use default constructors as much as possible during deserialization.
`UseDoubleForDecimals` Feature that determines whether to deserialize decimal numbers as double values.
`UseLongForInts` Feature that determines how "small" JSON integral (non-floating-point) numbers -- ones that fit in 32-bit signed integer (`int`) -- are bound when target type is loosely typed as `Object` or `Number` (or within untyped `Map` or `Collection` context).
`UseNativeObject` Feature that determines whether to use native Java objects (HashMap, ArrayList) instead of FASTJSON's JSONObject and JSONArray during deserialization.

Field Summary

Fields
Modifier and Type Field and Description

long mask

Fields
Modifier and Type	Field and Description
`long`	`mask`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`isEnabled(long features)` Checks if this feature is enabled in the specified features bitmask.
`static boolean`	`isEnabled(long features, JSONReader.Feature feature)` Checks if the specified feature is enabled in the given features bitmask.
`static long`	`of(JSONReader.Feature[] features)` Combines the masks of the specified features into a single bitmask.
`static JSONReader.Feature`	`valueOf(java.lang.String name)` Returns the enum constant of this type with the specified name.
`static JSONReader.Feature[]`	`values()` Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum
clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Enum Constant Detail
  - FieldBased
```
public static final JSONReader.Feature FieldBased
```
    Feature that determines whether to use field-based deserialization instead of getter/setter-based deserialization. When enabled, fields are directly accessed rather than using getter and setter methods. This can improve performance but may bypass validation logic in setters.
    By default, this feature is disabled, meaning that getter/setter-based deserialization is used.
    
    Since:
    
    2.0.0
  - IgnoreNoneSerializable
```
public static final JSONReader.Feature IgnoreNoneSerializable
```
    Feature that determines whether to ignore non-serializable classes during deserialization. When enabled, classes that do not implement Serializable will be ignored rather than causing an exception to be thrown.
    By default, this feature is disabled, meaning that non-serializable classes are not ignored.
    
    Since:
    
    2.0.0
  - ErrorOnNoneSerializable
```
public static final JSONReader.Feature ErrorOnNoneSerializable
```
    Feature that determines whether to throw an exception when encountering non-serializable classes during deserialization. When enabled, an exception will be thrown if a class does not implement Serializable.
    By default, this feature is disabled, meaning that no exception is thrown for non-serializable classes.
    
    Since:
    
    2.0.14
  - SupportArrayToBean
```
public static final JSONReader.Feature SupportArrayToBean
```
    Feature that determines whether to support deserializing JSON arrays into Java beans. When enabled, JSON arrays can be mapped to Java bean properties, with each array element corresponding to a property in the bean.
    By default, this feature is disabled, meaning that array-to-bean conversion is not supported.
    
    Since:
    
    2.0.0
  - InitStringFieldAsEmpty
```
public static final JSONReader.Feature InitStringFieldAsEmpty
```
    Feature that determines whether to initialize string fields as empty strings instead of null values. When enabled, string fields will be initialized with empty strings ("") rather than null.
    By default, this feature is disabled, meaning that string fields are initialized with null values.
    
    Since:
    
    2.0.0
  - SupportAutoType
```
@Deprecated
public static final JSONReader.Feature SupportAutoType
```
    Deprecated. It is not safe to explicitly turn on autoType, it is recommended to use AutoTypeBeforeHandler
    
    Feature that enables automatic type detection during deserialization. It is not safe to explicitly turn on autoType, it is recommended to use AutoTypeBeforeHandler.
    This feature is deprecated and should not be used in production code.
    
    Since:
    
    2.0.0
  - SupportSmartMatch
```
public static final JSONReader.Feature SupportSmartMatch
```
    Feature that enables smart matching of field names during deserialization. When enabled, field names in JSON can be matched to Java bean properties in a case-insensitive manner or with other smart matching rules.
    By default, this feature is disabled, meaning that exact field name matching is required.
    
    Since:
    
    2.0.0
  - UseNativeObject
```
public static final JSONReader.Feature UseNativeObject
```
    Feature that determines whether to use native Java objects (HashMap, ArrayList) instead of FASTJSON's JSONObject and JSONArray during deserialization. When enabled, standard Java collections are used rather than FASTJSON-specific ones.
    By default, this feature is disabled, meaning that FASTJSON's JSONObject and JSONArray are used.
    
    Since:
    
    2.0.0
  - SupportClassForName
```
public static final JSONReader.Feature SupportClassForName
```
    Feature that enables support for Class.forName() during deserialization. When enabled, the deserializer can use Class.forName() to load classes by name.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - IgnoreSetNullValue
```
public static final JSONReader.Feature IgnoreSetNullValue
```
    Feature that determines whether to ignore null values when setting properties. When enabled, null values in JSON will not be set on Java bean properties, preserving their default values.
    By default, this feature is disabled, meaning that null values are set on properties.
    
    Since:
    
    2.0.0
  - UseDefaultConstructorAsPossible
```
public static final JSONReader.Feature UseDefaultConstructorAsPossible
```
    Feature that determines whether to use default constructors as much as possible during deserialization. When enabled, the deserializer will prefer to use default (no-argument) constructors when creating objects.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - UseBigDecimalForFloats
```
public static final JSONReader.Feature UseBigDecimalForFloats
```
    Feature that determines whether to deserialize floating-point numbers as BigDecimal when the target type is float. When enabled, float values will be represented with higher precision using BigDecimal.
    By default, this feature is disabled, meaning that standard float precision is used.
    
    Since:
    
    2.0.0
  - UseBigDecimalForDoubles
```
public static final JSONReader.Feature UseBigDecimalForDoubles
```
    Feature that determines whether to deserialize floating-point numbers as BigDecimal when the target type is double. When enabled, double values will be represented with higher precision using BigDecimal.
    By default, this feature is disabled, meaning that standard double precision is used.
    
    Since:
    
    2.0.0
  - ErrorOnEnumNotMatch
```
public static final JSONReader.Feature ErrorOnEnumNotMatch
```
    Feature that determines whether to throw an exception when an enum value in JSON does not match any of the defined enum constants. When enabled, an exception will be thrown if an unknown enum value is encountered.
    By default, this feature is disabled, meaning that unknown enum values are ignored.
    
    Since:
    
    2.0.0
  - TrimString
```
public static final JSONReader.Feature TrimString
```
    Feature that determines whether to trim whitespace from string values during deserialization. When enabled, leading and trailing whitespace will be removed from string values.
    By default, this feature is disabled, meaning that string values are not trimmed.
    
    Since:
    
    2.0.0
  - ErrorOnNotSupportAutoType
```
public static final JSONReader.Feature ErrorOnNotSupportAutoType
```
    Feature that determines whether to throw an exception when autoType is not supported. When enabled, an exception will be thrown if autoType functionality is not available.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - DuplicateKeyValueAsArray
```
public static final JSONReader.Feature DuplicateKeyValueAsArray
```
    Feature that determines how to handle duplicate keys in JSON objects. When enabled, duplicate keys will be stored as arrays rather than overwriting previous values.
    By default, this feature is disabled, meaning that duplicate keys overwrite previous values.
    
    Since:
    
    2.0.0
  - AllowUnQuotedFieldNames
```
public static final JSONReader.Feature AllowUnQuotedFieldNames
```
    Feature that determines whether to allow unquoted field names in JSON. When enabled, field names in JSON objects do not need to be enclosed in quotes.
    By default, this feature is disabled, meaning that field names must be quoted.
    
    Since:
    
    2.0.0
  - NonStringKeyAsString
```
public static final JSONReader.Feature NonStringKeyAsString
```
    Feature that determines whether to treat non-string keys as strings during deserialization. When enabled, keys in JSON objects that are not strings will be converted to string representation.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - Base64StringAsByteArray
```
public static final JSONReader.Feature Base64StringAsByteArray
```
    Feature that determines whether to treat Base64-encoded strings as byte arrays during deserialization. When enabled, strings that contain Base64-encoded data will be automatically decoded to byte arrays.
    By default, this feature is disabled.
    
    Since:
    
    2.0.13
  - IgnoreCheckClose
```
public static final JSONReader.Feature IgnoreCheckClose
```
    Feature that determines whether to ignore checking for resource cleanup. When enabled, the deserializer will not perform checks to ensure proper resource cleanup.
    By default, this feature is disabled.
    
    Since:
    
    2.0.16
  - ErrorOnNullForPrimitives
```
public static final JSONReader.Feature ErrorOnNullForPrimitives
```
    Feature that determines whether to throw an exception when null values are encountered for primitive types during deserialization. When enabled, an exception will be thrown if a null value is found for a primitive type field.
    By default, this feature is disabled, meaning that primitive types are initialized with default values.
    
    Since:
    
    2.0.20
  - NullOnError
```
public static final JSONReader.Feature NullOnError
```
    Feature that determines whether to return null on error during deserialization. When enabled, errors during deserialization will result in null values rather than exceptions.
    By default, this feature is disabled.
    
    Since:
    
    2.0.20
  - IgnoreAutoTypeNotMatch
```
public static final JSONReader.Feature IgnoreAutoTypeNotMatch
```
    Feature that determines whether to ignore autoType mismatches during deserialization. When enabled, mismatches between expected and actual types in autoType scenarios will be ignored.
    By default, this feature is disabled.
    
    Since:
    
    2.0.21
  - NonZeroNumberCastToBooleanAsTrue
```
public static final JSONReader.Feature NonZeroNumberCastToBooleanAsTrue
```
    Feature that determines whether to cast non-zero numbers to boolean true during deserialization. When enabled, any non-zero numeric value will be treated as true when converting to boolean.
    By default, this feature is disabled.
    
    Since:
    
    2.0.24
  - IgnoreNullPropertyValue
```
public static final JSONReader.Feature IgnoreNullPropertyValue
```
    Feature that determines whether to ignore null property values during deserialization. When enabled, properties with null values in JSON will be ignored rather than set to null.
    By default, this feature is disabled.
    
    Since:
    
    2.0.40
  - ErrorOnUnknownProperties
```
public static final JSONReader.Feature ErrorOnUnknownProperties
```
    Feature that determines whether to throw an exception when unknown properties are encountered during deserialization. When enabled, an exception will be thrown if JSON contains properties that do not exist in the target class.
    By default, this feature is disabled, meaning that unknown properties are ignored.
    
    Since:
    
    2.0.42
  - EmptyStringAsNull
```
public static final JSONReader.Feature EmptyStringAsNull
```
    Feature that determines whether to convert empty strings to null values during deserialization. When enabled, empty string values ("") in JSON will be converted to null values.
    By default, this feature is disabled, meaning that empty strings are preserved as empty strings.
    
    Since:
    
    2.0.48
  - NonErrorOnNumberOverflow
```
public static final JSONReader.Feature NonErrorOnNumberOverflow
```
    Feature that determines whether to avoid throwing exceptions on number overflow during deserialization. When enabled, numeric overflow conditions will not cause exceptions to be thrown.
    By default, this feature is disabled, meaning that number overflow will cause exceptions.
    
    Since:
    
    2.0.48
  - UseBigIntegerForInts
```
public static final JSONReader.Feature UseBigIntegerForInts
```
    Feature that determines whether JSON integral (non-floating-point) numbers are to be deserialized into BigIntegers if only generic type description (either Object or Number, or within untyped Map or Collection context) is available. If enabled such values will be deserialized as BigIntegers; if disabled, will be deserialized as "smallest" available type, which is either Integer, Long or BigInteger, depending on number of digits.
    Feature is disabled by default, meaning that "untyped" integral numbers will by default be deserialized using whatever is the most compact integral type, to optimize efficiency.
    
    Since:
    
    2.0.51
  - UseLongForInts
```
public static final JSONReader.Feature UseLongForInts
```
    Feature that determines how "small" JSON integral (non-floating-point) numbers -- ones that fit in 32-bit signed integer (`int`) -- are bound when target type is loosely typed as Object or Number (or within untyped Map or Collection context). If enabled, such values will be deserialized as Long; if disabled, they will be deserialized as "smallest" available type, Integer.
    Note: if UseBigIntegerForInts is enabled, it has precedence over this setting, forcing use of BigInteger for all integral values.
    Feature is disabled by default, meaning that "untyped" integral numbers will by default be deserialized using Integer if value fits.
    
    Since:
    
    2.0.51
  - DisableSingleQuote
```
public static final JSONReader.Feature DisableSingleQuote
```
    Feature that disables the support for single quote. When enabled, single quotes are not allowed as string delimiters in JSON.
    By default, this feature is disabled, meaning that single quotes are supported.
    
    Since:
    
    2.0.53
  - UseDoubleForDecimals
```
public static final JSONReader.Feature UseDoubleForDecimals
```
    Feature that determines whether to deserialize decimal numbers as double values. When enabled, decimal values will be represented as double precision floating-point numbers.
    By default, this feature is disabled.
    
    Since:
    
    2.0.53
  - DisableReferenceDetect
```
public static final JSONReader.Feature DisableReferenceDetect
```
    Feature that disables reference detection during deserialization. When enabled, JSON references (such as those using $ref) will not be processed.
    By default, this feature is disabled, meaning that reference detection is enabled.
    
    Since:
    
    2.0.56
  - DisableStringArrayUnwrapping
```
public static final JSONReader.Feature DisableStringArrayUnwrapping
```
    Feature that disables unwrapping of single-element string arrays to scalar values. When enabled, JSON arrays containing a single string element will NOT be unwrapped, and will instead be returned as arrays. For example, ["value"] would be returned as ["value"] rather than "value".
    
    Since:
    
    2.0.60
- Field Detail
  - mask
```
public final long mask
```
- Method Detail
  - values
```
public static JSONReader.Feature[] values()
```
    Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:
```
for (JSONReader.Feature c : JSONReader.Feature.values())
    System.out.println(c);
```
    Returns:
    
    an array containing the constants of this enum type, in the order they are declared
  - valueOf
```
public static JSONReader.Feature valueOf(java.lang.String name)
```
    Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
    
    Parameters:
    
    name - the name of the enum constant to be returned.
    
    Returns:
    
    the enum constant with the specified name
    
    Throws:
    
    java.lang.IllegalArgumentException - if this enum type has no constant with the specified name
    
    java.lang.NullPointerException - if the argument is null
  - of
```
public static long of(JSONReader.Feature[] features)
```
    Combines the masks of the specified features into a single bitmask.
    
    Parameters:
    
    features - The features to combine
    
    Returns:
    
    A bitmask representing the combined features, or 0 if features is null
  - isEnabled
```
public boolean isEnabled(long features)
```
    Checks if this feature is enabled in the specified features bitmask.
    
    Parameters:
    
    features - The features bitmask to check
    
    Returns:
    
    true if this feature is enabled, false otherwise
  - isEnabled
```
public static boolean isEnabled(long features,
                                JSONReader.Feature feature)
```
    Checks if the specified feature is enabled in the given features bitmask.
    
    Parameters:
    
    features - The features bitmask to check
    
    feature - The feature to check for
    
    Returns:
    
    true if the specified feature is enabled, false otherwise

Enum JSONReader.Feature

Enum Constant Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Enum

Methods inherited from class java.lang.Object

Enum Constant Detail

FieldBased

IgnoreNoneSerializable

ErrorOnNoneSerializable

SupportArrayToBean

InitStringFieldAsEmpty

SupportAutoType

SupportSmartMatch

UseNativeObject

SupportClassForName

IgnoreSetNullValue

UseDefaultConstructorAsPossible

UseBigDecimalForFloats

UseBigDecimalForDoubles

ErrorOnEnumNotMatch

TrimString

ErrorOnNotSupportAutoType

DuplicateKeyValueAsArray

AllowUnQuotedFieldNames

NonStringKeyAsString

Base64StringAsByteArray

IgnoreCheckClose

ErrorOnNullForPrimitives

NullOnError

IgnoreAutoTypeNotMatch

NonZeroNumberCastToBooleanAsTrue

IgnoreNullPropertyValue

ErrorOnUnknownProperties

EmptyStringAsNull

NonErrorOnNumberOverflow

UseBigIntegerForInts

UseLongForInts

DisableSingleQuote

UseDoubleForDecimals

DisableReferenceDetect

DisableStringArrayUnwrapping

Field Detail

mask

Method Detail

values

valueOf

of

isEnabled

isEnabled