Question

I’m puzzled as to why using a default inclusion of jackson that Spring seems to have customised the default Jackson configuration.

One setting it’s messing with is WRITE_DATES_AS_TIMESTAMPS, the Jackson default is true however Spring has somewhere changed this to false and also provided a date format.

Where in the world is this happening? I want my dates to remain serialised as numbers.

UPDATE: Turns out it’s not spring that’s causing the problem, it’s actually hibernates proxy classes causing the problem. For some reason if hibernate has a type-mapping of type="date" it serialises as a date string, though if its type="timestamp" it serialises as expected. Rather than spend too much time looking into this I’ve decided to just change all my mappings to timestamp for now.

Answer 1

Starting with 3.1 M1 you can specify jackson custom configuration by registering an HttpMessageConverters through a sub-element of mvc:annotation-driven.

See Spring 3.1 MVC Namespace Improvements

See SPR-7504 Make it easier to add new Message Converters to AnnotationMethodHandlerAdapter

Exemple:

<bean id="jacksonObjectMapper" class="x.y.z.CustomObjectMapper">                
</bean>

<mvc:annotation-driven>
    <mvc:message-converters>
       <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
           <property name="objectMapper" ref="jacksonObjectMapper" />
       </bean>
       </mvc:message-converters>
</mvc:annotation-driven>

The CustomObjectMapper Object

    @Component("jacksonObjectMapper")
    public class CustomObjectMapper extends ObjectMapper {

        @PostConstruct
        public void afterPropertiesSet() throws Exception {

            SerializationConfig serialConfig = getSerializationConfig()     
                        .withDateFormat(null);

                  //any other configuration

            this.setSerializationConfig(serialConfig);
        }
    }

SerializationConfig .withDateFormat

In addition to constructing instance with specified date format, will enable or disable
Feature.WRITE_DATES_AS_TIMESTAMPS (enable if format set as null; disable if non-null)