JSONWriter.Feature

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

All Implemented Interfaces:

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

Enclosing class:

JSONWriter
```
public static enum JSONWriter.Feature
extends java.lang.Enum<JSONWriter.Feature>
```
Feature is used to control the behavior of JSON writing and serialization in FASTJSON2. Each feature represents a specific configuration option that can be enabled or disabled to customize how Java objects are serialized to JSON format.
Features can be enabled in several ways:
- Using factory methods like JSONWriter.of(Feature...)
- Using JSONWriter.config(Feature...) method
- Using JSONFactory.getDefaultWriterFeatures() for global configuration
Example usage:
```
 // Enable PrettyFormat feature for this writer only
 try (JSONWriter writer = JSONWriter.of(JSONWriter.Feature.PrettyFormat)) {
     writer.writeAny(object);
     String json = writer.toString();
 }

 // Enable multiple features
 try (JSONWriter writer = JSONWriter.of(
         JSONWriter.Feature.PrettyFormat,
         JSONWriter.Feature.WriteMapNullValue)) {
     writer.writeAny(object);
     String json = writer.toString();
 }

 // Using context configuration
 JSONWriter.Context context = new JSONWriter.Context();
 context.config(JSONWriter.Feature.PrettyFormat);
 try (JSONWriter writer = JSONWriter.of(context)) {
     writer.writeAny(object);
     String json = writer.toString();
 }
 
```
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:

JSONWriter.Context, JSONFactory

Enum Constant Summary

Enum Constants
Enum Constant and Description
`BeanToArray` Feature that determines whether to serialize Java beans as JSON arrays instead of JSON objects.
`BrowserCompatible` Feature that enables browser-compatible JSON output.
`BrowserSecure` Feature that enables browser security measures during serialization.
`ErrorOnNoneSerializable` Feature that determines whether to throw an exception when encountering non-serializable classes during serialization.
`EscapeNoneAscii` Feature that specifies that all characters beyond 7-bit ASCII range (i.e.
`FieldBased` Feature that determines whether to use field-based serialization instead of getter-based serialization.
`IgnoreEmpty` Feature that determines whether to ignore empty values during serialization.
`IgnoreErrorGetter` Feature that determines whether to ignore errors when calling getter methods during serialization.
`IgnoreNoneSerializable` Feature that determines whether to ignore non-serializable classes during serialization.
`IgnoreNonFieldGetter` Feature that determines whether to ignore non-field getter methods during serialization.
`LargeObject` Feature that enables support for large objects during serialization.
`MapSortField` Deprecated. Use `SortMapEntriesByKeys` instead.
`NotWriteDefaultValue` Feature that determines whether to write default values during serialization.
`NotWriteEmptyArray` Deprecated. use IgnoreEmpty
`NotWriteHashMapArrayListClassName` Feature that determines whether to write class names for HashMap and ArrayList during serialization.
`NotWriteNumberClassName` Feature that determines whether to write class names for Number objects during serialization.
`NotWriteRootClassName` Feature that determines whether to write the root class name during serialization.
`NotWriteSetClassName` Feature that determines whether to write class names for Set collections during serialization.
`NullAsDefaultValue` Feature that determines whether to write default values instead of null values during serialization.
`OptimizedForAscii` Feature that enables optimization for ASCII characters during serialization.
`PrettyFormat` Feature that enables pretty-printed JSON output with formatting and indentation.
`PrettyFormatWith2Space` JSON formatting support using 2 spaces for indentation.
`PrettyFormatWith4Space` JSON formatting support using 4 spaces for indentation.
`ReferenceDetection` Feature that enables reference detection during serialization.
`SortMapEntriesByKeys` The serialized Map will first be sorted according to Key, and is used in some scenarios where serialized content needs to be signed.
`UnquoteFieldName` Feature that determines whether to write field names without quotes during serialization.
`UseSingleQuotes` Feature that determines whether to use single quotes instead of double quotes for strings.
`WriteBigDecimalAsPlain` Feature that determines whether to write BigDecimal values in plain format during serialization.
`WriteBooleanAsNumber` Feature that determines whether to write boolean values as numbers during serialization.
`WriteByteArrayAsBase64` Feature that determines whether to write byte arrays as Base64-encoded strings during serialization.
`WriteClassName` Feature that determines whether to write class names during serialization.
`WriteEnumsUsingName` Feature that determines whether to write enum values using their name during serialization.
`WriteEnumUsingOrdinal` Feature that determines whether to write enum values using their ordinal value during serialization.
`WriteEnumUsingToString` Feature that determines whether to write enum values using their toString() representation during serialization.
`WriteFloatSpecialAsString` Feature that determines whether to write float/double NaN and Infinite values as Strings.
`WriteLongAsString` Feature that determines whether to write long values as strings during serialization.
`WriteMapNullValue` Feature that determines whether to write null values for map entries during serialization.
`WriteNameAsSymbol` Feature that determines whether to write field names as symbols during serialization.
`WriteNonStringKeyAsString` Feature that determines whether to write non-string keys as strings during serialization.
`WriteNonStringValueAsString` Feature that determines whether to write non-string values as strings during serialization.
`WriteNullBooleanAsFalse` Feature that determines whether to write null booleans as false during serialization.
`WriteNullListAsEmpty` Feature that determines whether to write null lists as empty arrays during serialization.
`WriteNullNumberAsZero` Feature that determines whether to write null numbers as zero during serialization.
`WriteNulls` Feature that determines whether to write null values during serialization.
`WriteNullStringAsEmpty` Feature that determines whether to write null strings as empty strings during serialization.
`WritePairAsJavaBean` Feature that determines whether to write key-value pairs as Java beans during serialization.
`WriterUtilDateAsMillis` Feature that determines whether to write java.util.Date objects as milliseconds since epoch.
`WriteThrowableClassName` Feature that determines whether to write the class name of Throwable objects during serialization.

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 JSONWriter.Feature`	`valueOf(java.lang.String name)` Returns the enum constant of this type with the specified name.
`static JSONWriter.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 JSONWriter.Feature FieldBased
```
    Feature that determines whether to use field-based serialization instead of getter-based serialization. When enabled, fields are directly accessed rather than using getter methods. This can improve performance but may bypass validation logic in getters.
    By default, this feature is disabled, meaning that getter-based serialization is used.
    
    Since:
    
    2.0.0
  - IgnoreNoneSerializable
```
public static final JSONWriter.Feature IgnoreNoneSerializable
```
    Feature that determines whether to ignore non-serializable classes during serialization. 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 JSONWriter.Feature ErrorOnNoneSerializable
```
    Feature that determines whether to throw an exception when encountering non-serializable classes during serialization. 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:
    
    2.0.0
  - BeanToArray
```
public static final JSONWriter.Feature BeanToArray
```
    Feature that determines whether to serialize Java beans as JSON arrays instead of JSON objects. When enabled, bean properties will be serialized as array elements in the order they are defined, rather than as key-value pairs in an object.
    By default, this feature is disabled, meaning that beans are serialized as JSON objects.
    
    Since:
    
    2.0.0
  - WriteNulls
```
public static final JSONWriter.Feature WriteNulls
```
    Feature that determines whether to write null values during serialization. When enabled, null values will be included in the output JSON.
    By default, this feature is disabled, meaning that null values are omitted from the output.
    
    Since:
    
    2.0.0
  - WriteMapNullValue
```
public static final JSONWriter.Feature WriteMapNullValue
```
    Feature that determines whether to write null values for map entries during serialization. When enabled, null values in maps will be included in the output JSON.
    By default, this feature is disabled, meaning that null map values are omitted from the output.
    
    Since:
    
    2.0.0
  - BrowserCompatible
```
public static final JSONWriter.Feature BrowserCompatible
```
    Feature that enables browser-compatible JSON output. When enabled, the output will be formatted to be compatible with browser JavaScript engines.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - NullAsDefaultValue
```
public static final JSONWriter.Feature NullAsDefaultValue
```
    Feature that determines whether to write default values instead of null values during serialization. When enabled, default values (0 for numbers, false for booleans, empty string for strings) will be written instead of null values.
    By default, this feature is disabled, meaning that null values are handled according to other features.
    
    Since:
    
    2.0.0
  - WriteBooleanAsNumber
```
public static final JSONWriter.Feature WriteBooleanAsNumber
```
    Feature that determines whether to write boolean values as numbers during serialization. When enabled, boolean values will be serialized as 1 (for true) and 0 (for false) instead of true and false literals.
    By default, this feature is disabled, meaning that boolean values are written as true/false.
    
    Since:
    
    2.0.0
  - WriteNonStringValueAsString
```
public static final JSONWriter.Feature WriteNonStringValueAsString
```
    Feature that determines whether to write non-string values as strings during serialization. When enabled, numeric and other non-string values will be converted to their string representation.
    By default, this feature is disabled, meaning that values are written in their native JSON types.
    
    Since:
    
    2.0.0
  - WriteClassName
```
public static final JSONWriter.Feature WriteClassName
```
    Feature that determines whether to write class names during serialization. When enabled, class names will be included in the output JSON, typically using a special "@type" field.
    By default, this feature is disabled, meaning that class names are not included in the output.
    
    Since:
    
    2.0.0
  - NotWriteRootClassName
```
public static final JSONWriter.Feature NotWriteRootClassName
```
    Feature that determines whether to write the root class name during serialization. When enabled, the class name of the root object will be included in the output JSON.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - NotWriteHashMapArrayListClassName
```
public static final JSONWriter.Feature NotWriteHashMapArrayListClassName
```
    Feature that determines whether to write class names for HashMap and ArrayList during serialization. When enabled, class names for these common collection types will be omitted from the output.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - NotWriteDefaultValue
```
public static final JSONWriter.Feature NotWriteDefaultValue
```
    Feature that determines whether to write default values during serialization. When enabled, fields with default values (0 for numbers, false for booleans, etc.) will be omitted.
    By default, this feature is disabled, meaning that all field values are written regardless of whether they are default values.
    
    Since:
    
    2.0.0
  - WriteEnumsUsingName
```
public static final JSONWriter.Feature WriteEnumsUsingName
```
    Feature that determines whether to write enum values using their name during serialization. When enabled, enum values will be serialized as their name string rather than their ordinal value.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - WriteEnumUsingToString
```
public static final JSONWriter.Feature WriteEnumUsingToString
```
    Feature that determines whether to write enum values using their toString() representation during serialization. When enabled, enum values will be serialized using their toString() method rather than their name or ordinal.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - IgnoreErrorGetter
```
public static final JSONWriter.Feature IgnoreErrorGetter
```
    Feature that determines whether to ignore errors when calling getter methods during serialization. When enabled, exceptions thrown by getter methods will be ignored rather than propagated.
    By default, this feature is disabled, meaning that getter method exceptions are propagated.
    
    Since:
    
    2.0.0
  - PrettyFormat
```
public static final JSONWriter.Feature PrettyFormat
```
    Feature that enables pretty-printed JSON output with formatting and indentation. When enabled, the output JSON will be formatted with line breaks and indentation for readability.
    By default, this feature is disabled, meaning that JSON is output in compact form.
    
    Since:
    
    2.0.0
  - ReferenceDetection
```
public static final JSONWriter.Feature ReferenceDetection
```
    Feature that enables reference detection during serialization. When enabled, circular references and repeated objects will be detected and handled using reference markers to avoid infinite loops and duplicate serialization.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - WriteNameAsSymbol
```
public static final JSONWriter.Feature WriteNameAsSymbol
```
    Feature that determines whether to write field names as symbols during serialization. When enabled, field names will be written as symbol references rather than string literals.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - WriteBigDecimalAsPlain
```
public static final JSONWriter.Feature WriteBigDecimalAsPlain
```
    Feature that determines whether to write BigDecimal values in plain format during serialization. When enabled, BigDecimal values will be written without exponential notation when possible.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - UseSingleQuotes
```
public static final JSONWriter.Feature UseSingleQuotes
```
    Feature that determines whether to use single quotes instead of double quotes for strings. When enabled, string values will be enclosed in single quotes rather than double quotes.
    By default, this feature is disabled, meaning that double quotes are used.
    
    Since:
    
    2.0.0
  - MapSortField
```
public static final JSONWriter.Feature MapSortField
```
    Deprecated. Use SortMapEntriesByKeys instead.
    
    The serialized Map will first be sorted according to Key, and is used in some scenarios where serialized content needs to be signed. SortedMap and derived classes do not need to do this. This Feature does not work for LinkedHashMap.
    
    Since:
    
    2.0.0
  - WriteNullListAsEmpty
```
public static final JSONWriter.Feature WriteNullListAsEmpty
```
    Feature that determines whether to write null lists as empty arrays during serialization. When enabled, null collection values will be serialized as empty JSON arrays ([]) rather than null.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - WriteNullStringAsEmpty
```
public static final JSONWriter.Feature WriteNullStringAsEmpty
```
    Feature that determines whether to write null strings as empty strings during serialization. When enabled, null string values will be serialized as empty strings ("") rather than null.
    By default, this feature is disabled.
    
    Since:
    
    1.1
  - WriteNullNumberAsZero
```
public static final JSONWriter.Feature WriteNullNumberAsZero
```
    Feature that determines whether to write null numbers as zero during serialization. When enabled, null numeric values will be serialized as 0 rather than null.
    By default, this feature is disabled.
    
    Since:
    
    1.1
  - WriteNullBooleanAsFalse
```
public static final JSONWriter.Feature WriteNullBooleanAsFalse
```
    Feature that determines whether to write null booleans as false during serialization. When enabled, null boolean values will be serialized as false rather than null.
    By default, this feature is disabled.
    
    Since:
    
    1.1
  - NotWriteEmptyArray
```
public static final JSONWriter.Feature NotWriteEmptyArray
```
    Deprecated. use IgnoreEmpty
    
    Feature that determines whether to avoid writing empty arrays during serialization. When enabled, empty arrays will be omitted from the output rather than written as [].
    By default, this feature is disabled.
    
    Since:
    
    2.0.7
  - IgnoreEmpty
```
public static final JSONWriter.Feature IgnoreEmpty
```
    Feature that determines whether to ignore empty values during serialization. When enabled, empty collections, empty strings, and other empty values will be omitted from the output.
    By default, this feature is disabled.
    
    Since:
    
    2.0.51
  - WriteNonStringKeyAsString
```
public static final JSONWriter.Feature WriteNonStringKeyAsString
```
    Feature that determines whether to write non-string keys as strings during serialization. When enabled, map keys that are not strings will be converted to their string representation.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - WritePairAsJavaBean
```
public static final JSONWriter.Feature WritePairAsJavaBean
```
    Feature that determines whether to write key-value pairs as Java beans during serialization. When enabled, key-value pairs will be serialized using Java bean conventions.
    By default, this feature is disabled.
    
    Since:
    
    2.0.11
  - OptimizedForAscii
```
public static final JSONWriter.Feature OptimizedForAscii
```
    Feature that enables optimization for ASCII characters during serialization. When enabled, the serializer will use optimized paths for ASCII-only content.
    By default, this feature is disabled.
    
    Since:
    
    2.0.12
  - EscapeNoneAscii
```
public static final JSONWriter.Feature EscapeNoneAscii
```
    Feature that specifies that all characters beyond 7-bit ASCII range (i.e. code points of 128 and above) need to be output using format-specific escapes (for JSON, backslash escapes), if format uses escaping mechanisms (which is generally true for textual formats but not for binary formats). Feature is disabled by default.
    
    Since:
    
    2.0.12
  - WriteByteArrayAsBase64
```
public static final JSONWriter.Feature WriteByteArrayAsBase64
```
    Feature that determines whether to write byte arrays as Base64-encoded strings during serialization. When enabled, byte array values will be serialized as Base64-encoded strings rather than arrays of numbers.
    By default, this feature is disabled.
    
    Since:
    
    2.0.13
  - IgnoreNonFieldGetter
```
public static final JSONWriter.Feature IgnoreNonFieldGetter
```
    Feature that determines whether to ignore non-field getter methods during serialization. When enabled, only getter methods that correspond to actual fields will be considered.
    By default, this feature is disabled.
    
    Since:
    
    2.0.13
  - LargeObject
```
public static final JSONWriter.Feature LargeObject
```
    Feature that enables support for large objects during serialization. When enabled, the serializer will use configurations appropriate for very large object graphs.
    By default, this feature is disabled.
    
    Since:
    
    2.0.16
  - WriteLongAsString
```
public static final JSONWriter.Feature WriteLongAsString
```
    Feature that determines whether to write long values as strings during serialization. When enabled, long numeric values will be serialized as strings rather than numbers to avoid precision loss in JavaScript and other environments with limited integer precision.
    By default, this feature is disabled.
    
    Since:
    
    2.0.17
  - BrowserSecure
```
public static final JSONWriter.Feature BrowserSecure
```
    Feature that enables browser security measures during serialization. When enabled, the output will be formatted to be secure when used in browser environments.
    By default, this feature is disabled.
    
    Since:
    
    2.0.20
  - WriteEnumUsingOrdinal
```
public static final JSONWriter.Feature WriteEnumUsingOrdinal
```
    Feature that determines whether to write enum values using their ordinal value during serialization. When enabled, enum values will be serialized as their ordinal (position) rather than their name.
    By default, this feature is disabled.
    
    Since:
    
    2.0.20
  - WriteThrowableClassName
```
public static final JSONWriter.Feature WriteThrowableClassName
```
    Feature that determines whether to write the class name of Throwable objects during serialization. When enabled, the class name of exception and error objects will be included in the output.
    By default, this feature is disabled.
    
    Since:
    
    2.0.30
  - UnquoteFieldName
```
public static final JSONWriter.Feature UnquoteFieldName
```
    Feature that determines whether to write field names without quotes during serialization. When enabled, field names in JSON objects will not be enclosed in quotes.
    By default, this feature is disabled, meaning that field names are quoted.
    
    Since:
    
    2.0.33
  - NotWriteSetClassName
```
public static final JSONWriter.Feature NotWriteSetClassName
```
    Feature that determines whether to write class names for Set collections during serialization. When enabled, class names for Set collections will be omitted from the output.
    By default, this feature is disabled.
    
    Since:
    
    2.0.34
  - NotWriteNumberClassName
```
public static final JSONWriter.Feature NotWriteNumberClassName
```
    Feature that determines whether to write class names for Number objects during serialization. When enabled, class names for Number objects will be omitted from the output.
    By default, this feature is disabled.
    
    Since:
    
    2.0.34
  - SortMapEntriesByKeys
```
public static final JSONWriter.Feature SortMapEntriesByKeys
```
    The serialized Map will first be sorted according to Key, and is used in some scenarios where serialized content needs to be signed. SortedMap and derived classes do not need to do this.
    
    Since:
    
    2.0.48
  - PrettyFormatWith2Space
```
public static final JSONWriter.Feature PrettyFormatWith2Space
```
    JSON formatting support using 2 spaces for indentation. When enabled, pretty-printed JSON will use 2 spaces for each indentation level.
    This feature requires PrettyFormat to also be enabled.
    
    Since:
    
    2.0.54
  - PrettyFormatWith4Space
```
public static final JSONWriter.Feature PrettyFormatWith4Space
```
    JSON formatting support using 4 spaces for indentation. When enabled, pretty-printed JSON will use 4 spaces for each indentation level.
    This feature requires PrettyFormat to also be enabled.
    
    Since:
    
    2.0.54
  - WriterUtilDateAsMillis
```
public static final JSONWriter.Feature WriterUtilDateAsMillis
```
    Feature that determines whether to write java.util.Date objects as milliseconds since epoch. When enabled, Date objects will be serialized as numeric timestamps rather than formatted strings.
    By default, this feature is disabled.
    
    Since:
    
    2.0.0
  - WriteFloatSpecialAsString
```
public static final JSONWriter.Feature WriteFloatSpecialAsString
```
    Feature that determines whether to write float/double NaN and Infinite values as Strings. When enabled, NaN/Infinity will be serialized as "NaN", "Infinity", "-Infinity".
    
    Since:
    
    2.0.61
- Field Detail
  - mask
```
public final long mask
```
- Method Detail
  - values
```
public static JSONWriter.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 (JSONWriter.Feature c : JSONWriter.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 JSONWriter.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
  - 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

Enum JSONWriter.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

BeanToArray

WriteNulls

WriteMapNullValue

BrowserCompatible

NullAsDefaultValue

WriteBooleanAsNumber

WriteNonStringValueAsString

WriteClassName

NotWriteRootClassName

NotWriteHashMapArrayListClassName

NotWriteDefaultValue

WriteEnumsUsingName

WriteEnumUsingToString

IgnoreErrorGetter

PrettyFormat

ReferenceDetection

WriteNameAsSymbol

WriteBigDecimalAsPlain

UseSingleQuotes

MapSortField

WriteNullListAsEmpty

WriteNullStringAsEmpty

WriteNullNumberAsZero

WriteNullBooleanAsFalse

NotWriteEmptyArray

IgnoreEmpty

WriteNonStringKeyAsString

WritePairAsJavaBean

OptimizedForAscii

EscapeNoneAscii

WriteByteArrayAsBase64

IgnoreNonFieldGetter

LargeObject

WriteLongAsString

BrowserSecure

WriteEnumUsingOrdinal

WriteThrowableClassName

UnquoteFieldName

NotWriteSetClassName

NotWriteNumberClassName

SortMapEntriesByKeys

PrettyFormatWith2Space

PrettyFormatWith4Space

WriterUtilDateAsMillis

WriteFloatSpecialAsString

Field Detail

mask

Method Detail

values

valueOf

isEnabled