com.fasterxml.jackson.annotation

Annotation Type JsonInclude

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

Annotation used to indicate when value of the annotated property (when used for a field, method or constructor parameter), or all properties of the annotated class, is to be serialized. Without annotation property values are always included, but by using this annotation one can specify simple exclusion rules to reduce amount of properties to write out.

Note that the main inclusion criteria (one annotated with value()) is checked on Java object level, for the annotated type, and NOT on JSON output -- so even with JsonInclude.Include.NON_NULL it is possible that JSON null values are output, if object reference in question is not `null`. An example is AtomicReference instance constructed to reference null value: such a value would be serialized as JSON null, and not filtered out.

To base inclusion on value of contained value(s), you will typically also need to specify content() annotation; for example, specifying only value() as JsonInclude.Include.NON_EMPTY for a {link java.util.Map} would exclude Maps with no values, but would include Maps with `null` values. To exclude Map with only `null` value, you would use both annotations like so:

public class Bean {
    @JsonInclude(value=Include.NON_EMPTY, content=Include.NON_NULL)
   public Map<String,String> entries;
}

Similarly you could exclude Maps that only contain "empty" elements, or "non-default" values (see JsonInclude.Include.NON_EMPTY and JsonInclude.Include.NON_DEFAULT for more details).

In addition to `Map`s, `content` concept is also supported for referential types (like AtomicReference). Note that `content` is NOT currently (as of Jackson 2.9) supported for arrays or Collections, but supported may be added in future versions.

Since:

2.0

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
JsonInclude.Include	content Inclusion rule to use for entries ("content") of annotated Maps and referential types (like AtomicReference); defaults to JsonInclude.Include.ALWAYS.
Class<?>	contentFilter Specifies type of "Filter Object" to use in case content() is JsonInclude.Include.CUSTOM: if so, an instance is created by calling HandlerInstantiator (of ObjectMapper), which by default simply calls zero-argument constructor of the Filter Class.
JsonInclude.Include	value Inclusion rule to use for instances (values) of types (Classes) or properties annotated; defaults to JsonInclude.Include.ALWAYS.
Class<?>	valueFilter Specifies type of "Filter Object" to use in case value() is JsonInclude.Include.CUSTOM: if so, an instance is created by calling HandlerInstantiator (of ObjectMapper), which by default simply calls zero-argument constructor of the Filter Class.

Element Detail

value

public abstract JsonInclude.Include value

Inclusion rule to use for instances (values) of types (Classes) or properties annotated; defaults to JsonInclude.Include.ALWAYS.

Default:

com.fasterxml.jackson.annotation.JsonInclude.Include.ALWAYS

content

public abstract JsonInclude.Include content

Inclusion rule to use for entries ("content") of annotated Maps and referential types (like AtomicReference); defaults to JsonInclude.Include.ALWAYS.

Since:

2.5

Default:

com.fasterxml.jackson.annotation.JsonInclude.Include.ALWAYS

valueFilter

public abstract Class<?> valueFilter

Specifies type of "Filter Object" to use in case value() is JsonInclude.Include.CUSTOM: if so, an instance is created by calling HandlerInstantiator (of ObjectMapper), which by default simply calls zero-argument constructor of the Filter Class.

Whether value if is to be included or not is determined by calling Filter's equals(value) method: if it returns true value is NOT included (it is "filtered out"); if false value IS included ("not filtered out").

Since:

2.9

Default:

java.lang.Void.class

contentFilter

public abstract Class<?> contentFilter

Specifies type of "Filter Object" to use in case content() is JsonInclude.Include.CUSTOM: if so, an instance is created by calling HandlerInstantiator (of ObjectMapper), which by default simply calls zero-argument constructor of the Filter Class.

Whether content value if is to be included or not is determined by calling Filter's equals(value) method: if it returns true content value is NOT included (it is "filtered out"); if false content value IS included ("not filtered out").

Since:

2.9

Default:

java.lang.Void.class