I'm having a rather particular problem with heap space and the
DefaultContentTypeHandlerManager in the struts rest plugin. I've got a
model driven rest controller with a few different methods that return rather
large result sets and it's causing heap space issues when the content type
handler tries to create a json string out of the result array. I traced the
problem through to when the content type handler being passed a StringWriter
object to output to, eventually it tries to resize some internal
representation of the string and we get a heap space error. I'd prefer to
write directly to the response output stream and not have the whole response
string buffered in memory. So, I wrote my own extension of
DefaultContentTypeHandlerManager that will pass my custom JSON content
handler the response stream instead of a StringWriter. All seems well,
except that I can't seem to find a way to override the class type of the
ContentTypeHandlerManager. Here's my struts.xml:
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd";>
<struts>
<constant name="struts.convention.package.locators" value="leadsService"/>
<constant name="struts.convention.action.suffix" value="Controller"/>
<constant name="struts.convention.action.mapAllMatches" value="true"/>
<constant name="struts.convention.default.parent.package"
value="rest-default"/>
<constant name="struts.convention.result.path" value="/WEB-INF/templates/"
/>
<constant name="struts.rest.defaultExtension" value="json" />
<bean name="myJson"
type="org.apache.struts2.rest.handler.ContentTypeHandler"
class="com.myCode.LeadsJsonHandler" />
<bean type="org.apache.struts2.rest.ContentTypeHandlerManager"
class="com.myCode.MyContentTypeHandlerManager" />
</struts>
And my struts.properties:
struts.rest.handlerOverride.json=myJson
Is it even possible to override the ContentTypeHandlerManager? When I try
to setup the bean in struts.xml as above, it just dies and throws this
error:
Caused by: Bean type interface
org.apache.struts2.rest.ContentTypeHandlerManager with the name default has
already been loaded by [unknown location] - bean -
file:/home/user/myCode/trunk/target/classes/struts.xml:12:142
at
com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.register(XmlConfigurationProvider.java:205)
A quick grep of the source has yielded me nothing so far, but any help in
the right direction to look would be most appreciated.
Thank you,
Stephen Huenneke
