Is Json Support in Spring MVC 3.2 broken? - json

Question

I am using Spring MVC in my application.
For a certain ajax call, I need to return JSON response.
Normally you would do that using #ReponseBody annotation.
Here is the piece of code I have used.
#RequestMapping(value ="/getClients", headers="Accept=*/*", produces = "application/json")
public #ResponseBody List<Map<String, Object>> getClients(#ModelAttribute("searchText") String searchText, ModelMap model){
logger.debug("Entering getClients with searchtext as : {}", searchText);
List<Map<String, Object>> autoCompleterResult = null;
try{
autoCompleterResult = clientService.getClientsForAutoCompleter(searchText);
logger.debug("Grid Result is : {}", autoCompleterResult );
}catch(Exception e){
logger.error("Exception occured", e);
}
return autoCompleterResult;
}
This works with Spring 3.1.4, but doesn't works with Spring 3.2 version.
Or is there some specific configuration I need to do for this to work with Spring 3.2?
MVC Config
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd">
<mvc:annotation-driven />
<mvc:resources location="/css/**" mapping="/css/" />
<mvc:resources location="/js/**" mapping="/js/" />
<mvc:resources location="/images/**" mapping="/images/" />
<bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<property name="exceptionMappings">
<props>
<prop key="java.lang.Exception">error</prop>
</props>
</property>
</bean>
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
<property name="prefix" value="/WEB-INF/views/" />
<property name="suffix" value=".jsp" />
</bean>
<context:component-scan base-package="com.controllers" />
<context:property-placeholder location="classpath:application.properties"/>
PS : I have included Jackson jar in my class path.
Update
Stack Trace :
02 Aug 2013 11:55:00 DEBUG impl.DistributionPlatformRepositoryImpl (DistributionPlatformServiceImpl.java42) - Entering getPlatforms
02 Aug 2013 11:55:00 DEBUG impl.DistributionPlatformRepositoryImpl (DistributionPlatformRepositoryImpl.java40) - Entering getPlatforms
02 Aug 2013 11:55:00 DEBUG impl.DistributionPlatformRepositoryImpl (DistributionPlatformServiceImpl.java88) - Entering getPlatformsAaData
02 Aug 2013 11:55:00 DEBUG controllers.SearchPlatformController (SearchPlatformController.java56) - Grid Result is : {iTotalDisplayRecords=7, aaData=[[A, B, C, 7, D, E, C, In Active, 25], [A, T, B, 3, L, C, 001, In Active, 20]]}
02 Aug 2013 11:55:00 DEBUG annotation.ExceptionHandlerExceptionResolver (AbstractHandlerExceptionResolver.java132) - Resolving exception from handler [public java.util.Map<java.lang.String, java.lang.Object> com.controllers.SearchPlatformController.getPlatforms(com.model.form.SearchPlatformForm,org.springframework.ui.ModelMap)]: org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
02 Aug 2013 11:55:00 DEBUG annotation.ResponseStatusExceptionResolver (AbstractHandlerExceptionResolver.java132) - Resolving exception from handler [public java.util.Map<java.lang.String, java.lang.Object> com.controllers.SearchPlatformController.getPlatforms(com.model.form.SearchPlatformForm,org.springframework.ui.ModelMap)]: org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
02 Aug 2013 11:55:00 DEBUG support.DefaultHandlerExceptionResolver (AbstractHandlerExceptionResolver.java132) - Resolving exception from handler [public java.util.Map<java.lang.String, java.lang.Object> com.controllers.SearchPlatformController.getPlatforms(com.model.form.SearchPlatformForm,org.springframework.ui.ModelMap)]: org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
02 Aug 2013 11:55:00 DEBUG servlet.DispatcherServlet (DispatcherServlet.java999) - Null ModelAndView returned to DispatcherServlet with name 'managedaccounts': assuming HandlerAdapter completed request handling
02 Aug 2013 11:55:00 DEBUG servlet.DispatcherServlet (FrameworkServlet.java951) - Successfully completed request

Answer 1

Finally after lot of searching I was able solve this. All thanks to Stackoverflow.
Please refer to the following link :
https://stackoverflow.com/a/13939290/1061430
Basically following section was required to be included in the MVC config file :
<mvc:annotation-driven content-negotiation-manager="contentNegotiationManager"/>
<bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">
<!-- Turn off working out content type based on URL file extension, should fall back to looking at the Accept headers -->
<property name="favorPathExtension" value="false" />
</bean>
Thanks again stackoverflow.

Answer 2

Just include the jackson jars into your project and spring will automatically detect it's presence and use it to serialize your objects.
Update
I saw someone has voted this answer down without clarifying why. This is a bit awkward. Especially since the statement is true ;)
So here's a piece quoted from http://blog.springsource.org/2010/01/25/ajax-simplifications-in-spring-3-0/
Underneath the covers, Spring MVC delegates to a HttpMessageConverter to perform the serialization. In this case, Spring MVC invokes a MappingJacksonHttpMessageConverter built on the Jackson JSON processor. This implementation is enabled automatically when you use the mvc:annotation-driven configuration element with Jackson present in your classpath.

Answer 3

What version of Jackson you using? Jackson 2.1.0 works great with Spring 3.2 of me with next maven dependencies:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.1.0</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.1.0</version>
</dependency>