Question

lets say I have two methods in my controller to support both json and xml.

@RequestMapping(value = "/get/response.json", method = RequestMethod.GET)
@Cacheable(JSON_CACHE)
public @ResponseBody JSONResponse getJsonResponse(){
    return responseService.getJsonResponse();
}
@RequestMapping(value = "/get/response.xml", method = RequestMethod.GET)
@Cacheable(XML_CACHE)
public  @ResponseBody XMLResponse getXmlResponse(){
    return responseService.getXmlResponse();
}

And two message converters, marshalling my objects into suitable response.

<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
    <property name="messageConverters">
        <list>
            <ref bean="jsonConverter"/>
            <ref bean="xmlConverter" />
        </list>
    </property>
</bean>

The problem is that Spring 3.1, even though method is annotated with @Cachable, still invokes marshaller for every call. It caches state of the object before marshalling.
This is not acceptable because performance is crucial here and marshalling is too expensive for me. I expected Spring to cache the final response in such case. Am I doing something wrong here?

Answer 1

To avoid this issue ehcache web caching can be used: http://www.ehcache.org/documentation/user-guide/web-caching

It works by simply adding filter to web.xml and provides caching of HTTP responses.

<filter>
    <filter-name>SimpleCachingHeadersPageCachingFilter</filter-name>
    <filter-class>net.sf.ehcache.constructs.web.filter.SimpleCachingHeadersPageCachingFilter
    </filter-class>
    <init-param>
        <param-name>suppressStackTrace</param-name>
        <param-value>false</param-value>
    </init-param>
    <init-param>
        <param-name>cacheName</param-name>
        <param-value>CachedPage2Cache</param-value>
    </init-param>
</filter>

<filter-mapping>
    <filter-name>SimpleCachingHeadersPageCachingFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>