com.fasterxml.jackson.annotation

Annotation Type JsonFormat

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

General-purpose annotation used for configuring details of how values of properties are to be serialized. Unlike most other Jackson annotations, annotation does not have specific universal interpretation: instead, effect depends on datatype of property being annotated (or more specifically, deserializer and serializer being used).

Common uses include choosing between alternate representations -- for example, whether Date is to be serialized as number (Java timestamp) or String (such as ISO-8601 compatible time value) -- as well as configuring exact details with pattern() property.

As of Jackson 2.1, known special handling include:

• Date: Shape can be JsonFormat.Shape.STRING or JsonFormat.Shape.NUMBER; pattern may contain SimpleDateFormat-compatible pattern definition.

Jackson 2.1 added following new features:

• Can now be used on Classes (types) as well, for modified default behavior, possibly overridden by per-property annotation
• Enums: Shapes JsonFormat.Shape.STRING and JsonFormat.Shape.NUMBER can be used to change between numeric (index) and textual (name or toString()); but it is also possible to use JsonFormat.Shape.OBJECT to serialize (but not deserialize) Enums as JSON Objects (as if they were POJOs). NOTE: serialization as JSON Object only works with class annotation; will not work as per-property annotation.
• Collections can be serialized as (and deserialized from) JSON Objects, if JsonFormat.Shape.OBJECT is used. NOTE: can ONLY be used as class annotation; will not work as per-property annotation.

In Jackson 2.4:

• Number subclasses can be serialized as full objects if JsonFormat.Shape.OBJECT is used. Otherwise the default behavior of serializing to a scalar number value will be preferred. NOTE: can ONLY be used as class annotation; will not work as per-property annotation.

Since:

2.0

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
String	locale Locale to use for serialization (if needed).
String	pattern Datatype-specific additional piece of configuration that may be used to further refine formatting aspects.
JsonFormat.Shape	shape Structure to use for serialization: definition of mapping depends on datatype, but usually has straight-forward counterpart in data format (JSON).
String	timezone TimeZone to use for serialization (if needed).

Element Detail

pattern

public abstract String pattern

Datatype-specific additional piece of configuration that may be used to further refine formatting aspects. This may, for example, determine low-level format String used for Date serialization; however, exact use is determined by specific JsonSerializer

Default:

""

shape

public abstract JsonFormat.Shape shape

Structure to use for serialization: definition of mapping depends on datatype, but usually has straight-forward counterpart in data format (JSON). Note that commonly only a subset of shapes is available; and if 'invalid' value is chosen, defaults are usually used.

Default:

com.fasterxml.jackson.annotation.JsonFormat.Shape.ANY

locale

public abstract String locale

Locale to use for serialization (if needed). Special value of DEFAULT_LOCALE can be used to mean "just use the default", where default is specified by the serialization context, which in turn defaults to system defaults (Locale.getDefault()) unless explicitly set to another locale.

Default:

"##default"

timezone

public abstract String timezone

TimeZone to use for serialization (if needed). Special value of DEFAULT_TIMEZONE can be used to mean "just use the default", where default is specified by the serialization context, which in turn defaults to system defaults (TimeZone.getDefault()) unless explicitly set to another locale.

Default:

"##default"