com.fasterxml.jackson.annotation

Annotation Type JsonProperty

@Target(value={ANNOTATION_TYPE,FIELD,METHOD,PARAMETER})
 @Retention(value=RUNTIME)
public @interface JsonProperty

Marker annotation that can be used to define a non-static method as a "setter" or "getter" for a logical property (depending on its signature), or non-static object field to be used (serialized, deserialized) as a logical property.

Default value ("") indicates that the field name is used as the property name without any modifications, but it can be specified to non-empty value to specify different name. Property name refers to name used externally, as the field name in JSON objects.

Starting with Jackson 2.6 this annotation may also be used to change serialization of Enum like so:

public enum MyEnum {
     @JsonProperty("theFirstValue") THE_FIRST_VALUE,
     @JsonProperty("another_value") ANOTHER_VALUE;
}

as an alternative to using JsonValue annotation.

Starting with Jackson 2.12 it is also possible to specify namespace of property: this property is only used by certain format backends (most notably XML).

Field Summary

Fields

Modifier and Type	Fields and Description
static int	INDEX_UNKNOWN Marker value used to indicate that no index has been specified.
static String	USE_DEFAULT_NAME Special value that indicates that handlers should use the default name (derived from method or field name) for property.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
JsonProperty.Access	access Optional property that may be used to change the way visibility of accessors (getter, field-as-getter) and mutators (constructor parameter, setter, field-as-setter) is determined, either so that otherwise non-visible accessors (like private getters) may be used; or that otherwise visible accessors are ignored.
String	defaultValue Property that may be used to document expected default value for the property: most often used as source information for generating schemas (like JSON Schema or protobuf/thrift schema), or documentation.
int	index Property that indicates numerical index of this property (relative to other properties specified for the Object).
String	namespace Optional namespace to use with data formats that support such concept (specifically XML); if so, used with value() to construct fully-qualified name.
boolean	required Property that indicates whether a value (which may be explicit null) is expected for property during deserialization or not.
String	value Defines name of the logical property, i.e.

Field Detail

USE_DEFAULT_NAME

public static final String USE_DEFAULT_NAME

Special value that indicates that handlers should use the default name (derived from method or field name) for property.

Since:

2.1

INDEX_UNKNOWN

public static final int INDEX_UNKNOWN

Marker value used to indicate that no index has been specified. Used as the default value as annotations do not allow "missing" values.

Since:

2.4

Element Detail

value

public abstract String value

Defines name of the logical property, i.e. JSON object field name to use for the property. If value is empty String (which is the default), will try to use name of the field that is annotated. Note that there is no default name available for constructor arguments, meaning that Empty String is not a valid value for constructor arguments.

Default:

""

namespace

public abstract String namespace

Optional namespace to use with data formats that support such concept (specifically XML); if so, used with value() to construct fully-qualified name.

Since:

2.12

Default:

""

required

public abstract boolean required

Property that indicates whether a value (which may be explicit null) is expected for property during deserialization or not. If expected, BeanDeserialized should indicate this as a validity problem (usually by throwing an exception, but this may be sent via problem handlers that can try to rectify the problem, for example, by supplying a default value).

Note that as of 2.6, this property is only used for Creator Properties, to ensure existence of property value in JSON: for other properties (ones injected using a setter or mutable field), no validation is performed. Support for those cases may be added in future. State of this property is exposed via introspection, and its value is typically used by Schema generators, such as one for JSON Schema.

Since:

2.0

Default:

false

index

public abstract int index

Property that indicates numerical index of this property (relative to other properties specified for the Object). This index is typically used by binary formats, but may also be useful for schema languages and other tools.

Since:

2.4

Default:

-1

defaultValue

public abstract String defaultValue

Property that may be used to document expected default value for the property: most often used as source information for generating schemas (like JSON Schema or protobuf/thrift schema), or documentation. It may also be used by Jackson extension modules; core `jackson-databind` does not have any automated handling beyond simply exposing this value through bean property introspection.

It is possible that in future this annotation could be used for value defaulting, and especially for default values of Creator properties, since they support required() in 2.6 and above.

Since:

2.5

Default:

""

access

public abstract JsonProperty.Access access

Optional property that may be used to change the way visibility of accessors (getter, field-as-getter) and mutators (constructor parameter, setter, field-as-setter) is determined, either so that otherwise non-visible accessors (like private getters) may be used; or that otherwise visible accessors are ignored.

Default value os JsonProperty.Access.AUTO which means that access is determined solely based on visibility and other annotations.

Since:

2.6

Default:

com.fasterxml.jackson.annotation.JsonProperty.Access.AUTO