Apache CXF + Jackson

Some days ago I had a task for converting java HashMap to JSON responce, using Apache CXF framework. It was surprise for me that standart CXF JSON provider(Jettison) doesn't work with maps. As I didnt want to write my custom XMLAdapter, I desided to use Jackson, as it works with maps perfectly.

There are next steps to configure:

1. Add Jackson maven dependency

<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-jaxrs</artifactId>
    <version>1.9.7</version>
</dependency> 



2. Include Jackson provider bean into your service providers:

<bean id="jsonProvider" class="org.codehaus.jackson.jaxrs.JacksonJsonProvider"/>
<jaxrs:server id="clientService" address="/clientservice">
        <jaxrs:serviceBeans>
            <ref bean="clientBean" />
        </jaxrs:serviceBeans>
        <jaxrs:extensionMappings>
            <entry key="json" value="application/json"/>
            <entry key="xml" value="application/xml"/>
        </jaxrs:extensionMappings> 
        <jaxrs:providers>
            <ref bean="jaxbProvider"/>
        </jaxrs:providers>
 </jaxrs:server>

Now all JSON responces from "clientService" are generated by Jackson.
Also next Jackson configuration could be very usefull:

• Enable wrapping entities with root element.
• Exclude null values from JSON responce. 
This features are disabled by default. To enable it I created my custom ObjectMapper class, that extends from "org.codehaus.jackson.map.ObjectMapper"


import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig;
import org.codehaus.jackson.map.annotate.JsonSerialize;

public class CustomObjectMapper extends ObjectMapper{

    public CustomObjectMapper() {
    super();
    super.configure(SerializationConfig.Feature.WRAP_ROOT_VALUE, true);
    super.setSerializationInclusion(JsonSerialize.Inclusion.NON_NULL);
    }

}


Then added CustomObjectMapper to "jsonProvider" constructor:

<bean id="jacksonMapper" class="com.xproject.server.util.CustomObjectMapper" />
<bean id="jaxbProvider" class="org.codehaus.jackson.jaxrs.JacksonJsonProvider">
        <constructor-arg ref="jacksonMapper" />
 </bean>