liferay - respond to http request with json object in portlet -

i beginner in liferay portlet development , developing portlet receives http request, processes information , has return json object. problem portlet sends whole html page instead of json object. code:

httpservletresponse servletresponse = portalutil.gethttpservletresponse((renderresponse));              servletresponse.setheader("content-type", "application/json");             servletresponse.setcharacterencoding("application/json");             printwriter out = servletresponse.getwriter();             out.write(entityutils.tostring(responseentity));               out.flush();             out.close(); 

i execute in doview() method know not best practice, not concerned @ moment. can explain me how return json object read serveresponse, couldn't figure out how invoke it.

well, 1 thing notice, doview() responsible rendering of portlet. requirement can better achieved by
1 - processaction(portlet action) or
2 - serveresource(portlet ajax service).

to view, ajax request-response suitable case; need create resource url on portlet view. like:

<portlet:resourceurl var="ajaxresourceurl" /> 

add javascript method page, can generate ajax request portlet. method this,

<script type="text/javascript"> function _callajax(val1, val2){     var url = '<%=ajaxresourceurl %>';    // pass resource url created using scriplet / el.     jquery.ajax({     type : "post",     url : url,     cache:false,     datatype: "json",     data: {       value1: val1,    // parameters if want pass       value2: val2     },         success : function(data){         // whatever want response data     },     error : function(xmlhttprequest, textstatus, errorthrown){        alert(errorthrown);        alert(textstatus);     }   }); }; </script> 

call ajax method on button / link click event:

<input type="button" onclick="_callajax('val1', 'val2')" value="send" />  

and finally, in portlet's action listener class add following serveresource method, responsible handling ajax based request(s).

here can request parameters , generate response in sense want:

@override public void serveresource(resourcerequest request, resourceresponse response) throws portletexception,ioexception {  string value1 = paramutil.getstring(request , "value1", "default");    // request parameters string value2 = paramutil.getstring(request , "value2", "");  printwriter writer = response.getwriter();  jsonobject jsonobject = new jsonobject(); jsonobject.put(string key, boolean/long/collection/double/map/object value);  writer.write(jsonobject.tostring()); } 

thats it! hope, helpful :)