Package com.fasterxml.jackson.annotation
Annotation Interface JsonUnwrapped
@Target({ANNOTATION_TYPE,FIELD,METHOD,PARAMETER})
@Retention(RUNTIME)
public @interface JsonUnwrapped
Annotation used to indicate that a POJO-valued property should be
serialized "unwrapped" -- that is, if it would be serialized as Object value,
its properties are instead included as properties of its containing
Object -- and deserialized reproducing "missing" structure.
For example, consider case of POJO like:
public class Parent { public int age; public Name name; } public class Name { public String first, last; }which would normally be serialized as follows (assuming
@JsonUnwrapped
had no effect):
{ "age" : 18, "name" : { "first" : "Joey", "last" : "Sixpack" } }can be changed to this:
{ "age" : 18, "first" : "Joey", "last" : "Sixpack" }by changing Parent class to:
public class Parent { public int age; @JsonUnwrapped public Name name; }Annotation can only be added to properties, and not classes, as it is contextual. When values are deserialized "wrapping" is applied so that serialized output can be read back in.
Also note that annotation only applies if:
- Value is serialized as an Object value (can not unwrap Array values using this mechanism)
- Reading/writing is done using Jackson standard
BeanDeserializer
/BeanSerializer
; or custom deserializer/serializer MUST explicitly support similar operation. - Will not work with polymorphic type handling ("polymorphic deserialization")
Map
s or JsonNode
s: for these types you will
instead need to use JsonAnyGetter
and JsonAnySetter
to achieve
similar operation.-
Optional Element Summary
Optional ElementsModifier and TypeOptional ElementDescriptionboolean
Property that is usually only used when overriding (masking) annotations, using mix-in annotations.Optional property that can be used to add prefix String to use in front of names of properties that are unwrapped: this can be done for example to prevent name collisions.Optional property that can be used to add suffix String to append at the end of names of properties that are unwrapped: this can be done for example to prevent name collisions.
-
Element Details
-
enabled
boolean enabledProperty that is usually only used when overriding (masking) annotations, using mix-in annotations. Otherwise default value of 'true' is fine, and value need not be explicitly included.- Default:
- true
-
prefix
String prefixOptional property that can be used to add prefix String to use in front of names of properties that are unwrapped: this can be done for example to prevent name collisions.- Default:
- ""
-
suffix
String suffixOptional property that can be used to add suffix String to append at the end of names of properties that are unwrapped: this can be done for example to prevent name collisions.- Default:
- ""
-