christophercurrie/jackson-datatype-hibernate

Add-on module for Jackson JSON processor which handles Hibernate (http://www.hibernate.org/) datatypes; and specifically aspects of lazy-loading

Project to build Jackson (http://jackson.codehaus.org) module (jar) to support JSON serialization and deserialization of Hibernate (http://hibernate.org) specific datatypes and properties; especially lazy-loading aspects.

Status

As of version 2.0 module is usable and used by non-trivial number of developers and projects. Rough edges may still exist; please report any bugs you find.

Note: both Hibernate 3 and 4 are supported, but they require different jar, and Maven artifact names (and jar names differ). This document refers to "Hibernate 4" version, but changes with 3 should be little more than replacing "4" in names with "3".

Usage

Maven dependency

To use module on Maven-based projects, use following dependency:

<dependency>
  <groupId>com.fasterxml.jackson.datatype</groupId>
  <artifactId>jackson-datatype-hibernate4</artifactId>
  <version>2.2.3</version>
</dependency>    

(or whatever version is most up-to-date at the moment; note that you need to use "jackson-datatype-hibernate3" for Hibernate 3.x)

Registering module

Like all standard Jackson modules (libraries that implement Module interface), registration is done as follows:

ObjectMapper mapper = new ObjectMapper();
// for Hibernate 4.x:
mapper.registerModule(new Hibernate4Module());
// or, for Hibernate 3.6
mapper.registerModule(new Hibernate3Module());

after which functionality is available for all normal Jackson operations.

Note that there are actuall

Using with Spring MVC

Sub-class ObjectMapper and register the module (Hibernate 3 or 4)

public class HibernateAwareObjectMapper extends ObjectMapper {

    public HibernateAwareObjectMapper() {
        registerModule(new Hibernate4Module());
    }
}

Then add it as the objectmapper to be used

    <mvc:annotation-driven>
        <mvc:message-converters>
            <!-- Use the HibernateAware mapper instead of the default -->
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="path.to.your.HibernateAwareObjectMapper" />
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

If mvc:annotation-driven is not being used, it can be added as a jsonconverter to the messageconverters of RequestMappingHandlerAdapter.