Question

Thanks in advance any help.

I’m trying to get one of my controller methods to return JSON. Starting off with a simple test:

@RequestMapping(value="/myReqPath", method=RequestMethod.GET)
@ResponseBody
public Map<String, String> myJsonMethod() {

    Map<String, String> response = new TreeMap<String, String>();
    response.put("test", "test");

    return response;

}

It’s my understanding that I need <mvc:annotation-driven/> added to my servlet context to accomplish this. The problem is when I add it, it breaks my custom AnnotationMethodHandlerAdapter.

[B]How do I extract and add the needed parts of <mvc:annotation-driven/> to return JSON from the controller?[/B]

Here are the pertinent parts of my servlet config:

<!--Skipping this for now...
<mvc:annotation-driven/>
-->

<!-- JSON Marshaling -->
<util:constant id="jsonBasicClassIntrospector"
    static-field="org.codehaus.jackson.map.introspect.BasicClassIntrospector.instance" />
<bean id="jsonJaxbAnnotationIntrospector" 
    class="org.codehaus.jackson.xc.JaxbAnnotationIntrospector" />
<bean id="jsonVisibilityChecker" 
    class="org.codehaus.jackson.map.introspect.VisibilityChecker.Std"
    factory-method="defaultInstance" />
<bean id="jsonDefaultTypeFactory" 
    class="org.codehaus.jackson.map.type.TypeFactory"
    factory-method="defaultInstance" />
<bean id="jsonObjectMapper" class="org.codehaus.jackson.map.ObjectMapper">
    <property name="serializationConfig">
        <bean class="org.codehaus.jackson.map.SerializationConfig">
            <constructor-arg ref="jsonBasicClassIntrospector" />
            <constructor-arg ref="jsonJaxbAnnotationIntrospector" />
            <constructor-arg ref="jsonVisibilityChecker" />
            <constructor-arg><null/></constructor-arg>
            <constructor-arg><null/></constructor-arg>
            <constructor-arg ref="jsonDefaultTypeFactory" />
            <constructor-arg><null/></constructor-arg>
        </bean>
    </property>
    <property name="deserializationConfig">
        <bean class="org.codehaus.jackson.map.DeserializationConfig">
            <constructor-arg ref="jsonBasicClassIntrospector" />
            <constructor-arg ref="jsonJaxbAnnotationIntrospector" />
            <constructor-arg ref="jsonVisibilityChecker" />
            <constructor-arg><null/></constructor-arg>
            <constructor-arg><null/></constructor-arg>
            <constructor-arg ref="jsonDefaultTypeFactory" />
            <constructor-arg><null/></constructor-arg>
        </bean>
    </property>
</bean>

...

<!-- My custom  AnnotationMethodHandlerAdapter... -->
<bean id="sessionArgResolver" class="com.SessionParamArgumentResolver"/>
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
    <property name="customArgumentResolver" ref="sessionArgResolver"/>
</bean>

As it stands, my controller method is invoked however, the browser returns http status 406:
406 Not Acceptable – [url]http://localhost:8080/myApp/myReqPath[/url]

Answer 1

If you already have a custom AnnotationMethodHandlerAdapter declaration, you can just add a list of HttpMessageConverters to it:

<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
    <property name="customArgumentResolver" ref="sessionArgResolver"/>
    <property name = "messageConverters">
        <list>
            <bean 
                class = "org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
                <property name = "objectMapper" ref = "jsonObjectMapper" />
            </bean>
        </list>
    </property>
</bean>