Thursday, August 09, 2007

Data Services in Spring

In today's web applications the need for returning model data from controllers in XML/JSON format is quite common. Mostly these requirements are met by writing custom code in controllers. In this post I will present technical approach that would enable your applications to return data model in XML/JSON or data format of your choice to the web tier using Spring MVC without modifying your applications.

Basically the idea is to return XML(or JSON, etc) whenever we encounter a request to the controller with parameter returnData=XML. This can be accomplished by writing a HandlerInterceptorAdapter with postHandle method to do the following:

void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)

if ( request.getParamter("returnData") != null && request.getParamter("returnData")="XML" )

// add a XML Serializer to the model
// Find the model object names and add the list to model attribute "xmlModules"
// Set the view name to "xmlView"



In your xmlView (JSP or Velocity Template) for each attribute in xmlModules use the XML Serializer to generate XML and render it. There are few applications for this approach:

1. Enable front-end to readily use AJAX for existing controllers
2. Use this as a strategy to get a debug view of model data during development
3. Based on some additional key use this to get debug view from production for troubleshooting purpose


1. XStream for XML Serialization

Tags: java spring ajax

No comments:

Disqus for techtalk