This is a multi-module umbrella project for Jackson modules needed to support Java 8 features, especially with Jackson 2.x that only requires Java 7 for running (and until 2.7 only Java 6).
When used with Jackson 2.x, Java 8 support is provided via 3 separate modules:
@JsonProperty
annotation
com.fasterxml.jackson.module.paramnames.ParameterNamesModule
com.fasterxml.jackson.datatype.jsr310.JavaTimeModule
com.fasterxml.jackson.datatype.jsr310.JSR310TimeModule
JavaTimeModule
strongly recommended for new codeOptional
, OptionalLong
, OptionalDouble
com.fasterxml.jackson.datatype.jdk8.Jdk8Module
all of which are built from this repository, and accessed and used as separate Jackson modules (with separate Maven artifacts).
Jackson 3.0 changes things as it requires Java 8 to work and can thereby directly supported features.
Because of this parameter-names
and datatypes
modules are merged into jackson-databind
and need not be registered; datetime
module (JavaTimeModule
) remains separate module due to its size
and configurability options.
So you will only need to separately add "Java 8 Date/time" module (see above for description)
All modules are licensed under Apache License 2.0.
To include modules, you use some or all of:
<!-- Parameter names -->
<dependency>
<groupId>com.fasterxml.jackson.module</groupId>
<artifactId>jackson-module-parameter-names</artifactId>
</dependency>
<!-- Java 8 Date/time -->
<dependency>
<groupId>com.fasterxml.jackson.datatype</groupId>
<artifactId>jackson-datatype-jsr310</artifactId>
</dependency>
<!-- Java 8 Datatypes -->
<dependency>
<groupId>com.fasterxml.jackson.datatype</groupId>
<artifactId>jackson-datatype-jdk8</artifactId>
</dependency>
and either include versions directly, OR, preferably, import Jackson BOM that will specify consistent version set.
Note that the parent project -- jackson-modules-java8
-- is ONLY used as parent pom by
individual "child" modules, and DOES NOT have dependencies on them. This means that you should not depend on it
as that will not include child modules.
The most common mechanism (and one recommended by Jackson team) is to explicitly register modules you want. This is done by code like:
// Up to Jackson 2.9: (but not with 3.0)
ObjectMapper mapper = new ObjectMapper()
.registerModule(new ParameterNamesModule())
.registerModule(new Jdk8Module())
.registerModule(new JavaTimeModule()); // new module, NOT JSR310Module
// with 3.0 (or with 2.10 as alternative)
ObjectMapper mapper = JsonMapper.builder() // or different mapper for other format
.addModule(new ParameterNamesModule())
.addModule(new Jdk8Module())
.addModule(new JavaTimeModule())
// and possibly other configuration, modules, then:
.build();
Alternatively, you can also auto-discover these modules with:
ObjectMapper mapper = new ObjectMapper();
mapper.findAndRegisterModules();
Regardless of registration mechanism, after registration all functionality is available for all normal Jackson operations.
But do note that you should only either explicit OR automatic registration: DO NOT combine explicit and auto-registration. If you use both, only one of registrations will have effect. And selection of which one varies by module and settings:
MapperFeature.IGNORE_DUPLICATE_MODULE_REGISTRATIONS
is defined, the FIRST registration succeeds, rest ignored
Module.getTypeId()
; duplicate-detection requires that Module provides same for all instances (true for Modules provided by this repo)Also note that before Jackson 2.10, auto-registration would only register older JSR310Module
, and not newer
JavaTimeModule
-- this is due to backwards compatibility. This was changed in Jackson 2.10.
If you want "the other" version of the module but also use auto-registration, make sure to
register "other" module explicitly AFTER calling mapper.findAndRegisterModules()
.
Call after works because getTypeId()
provided by modules differs so they are not considered duplicates.
Following developers have committer access to this project.
jackson-databind
)See Wiki for more information (javadocs).