java - Dynamic form, with or without multipart/form-data -

i designing simple crud framework in java, in html page have dynamic form (2 multipart create , update file upload , 1 without fileupload , multipart delete). server side, request modulator checks parameters using request.getparametermap(); , checks hidden type input <input type="hidden" name="returntype" value="create"> whether create, update or delete operation. based on call necessary handlers.

note: form enctype , encoding set multipart/form-data note: parammap.size() returns 0 here , returntype getting null , getting null pointer exception.

if not use enctype , encoding @ runs fine, again file upload gives me exception encoding type shoud multipart/form-data. can me in way can have dynamic form can create crud? or why not able use request.getparametermap(); multipart/form-data :)

given below code of request modulator

public string identifynow()throws servletexception, java.io.ioexception {     uploadxmlagent uploadagent;     parammap=request.getparametermap();     if (parammap == null)         throw new servletexception(           "getparametermap returned null in: " + getclass().getname());      iterator=parammap.entryset().iterator();     system.out.println(parammap.size());     while(iterator.hasnext())     {         map.entry me=(map.entry)iterator.next();         if(me.getkey().equals("returntype"))         {             string[] arr=(string[])me.getvalue();             returntype=arr[0];         }     }      //identified based on returntype, instantiate appropriate handler      if(returntype.equals("create"))     {         uploadagent=new uploadxmlagent(realpath,request,parammap);         uploadagent.retrievexml();                     //some more operations           return uploadagent.uploadxml();     }     else if(returntype.equals("update"))     {         system.out.println("update");         uploadagent=new uploadxmlagent(realpath,request,parammap);         uploadagent.retrievexml();                     //some more operations         return uploadagent.uploadxml();     }     else if(returntype.equals("delete"))     {         //some operations     }     return returntype; } 

as per comment on other answer:

can use request.getparametermap(); in way multipart?

if sole requirement, create filter parsing work , prepares request parameter map parsed multipart items can continue using getparameter(), getparametermap() , consorts usual way in jsp/servlet. can find complete example of such filter here.