Dependant Dropdowns Using Ajax

rupalilakka (rupalilakka) — Tue, 20 Mar 2007 10:18:03 GMT
This code demonstrates using ajax for dependant combos.The sample application
below has 2 combo boxes 1.country 2.city.
OnChange event on the country should populate the corresponding cities in the
city dropdown.


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ajaxscripting.js

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GetAndPostExample

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package ajaxsample;



import java.io.*;

import java.net.*;

import javax.servlet.*;

import javax.servlet.http.*;

import org.apache.struts.action.Action;

import org.apache.struts.action.ActionForm;

import org.apache.struts.action.ActionForward;

import org.apache.struts.action.ActionMapping;

import java.util.ArrayList;

import org.apache.struts.action.ActionServlet;

import org.apache.struts.util.LabelValueBean;



public class GetAndPostExample extends Action {

    

    ServletContext context = null;

    

    public void setServlet(ActionServlet servlet)

    {

        context =  servlet.getServletContext();

    }

   public ActionForward execute(ActionMapping mapping, ActionForm inForm, 

           HttpServletRequest request, HttpServletResponse response) throws Exception {

           response.setContentType("text/xml");



          String optionSelected = request.getParameter("selcountry");        

         //Build the response text

         

         SampleForm sform = (SampleForm)inForm;

         ArrayList countries = (ArrayList)context.getAttribute("countries");

         ArrayList states = (ArrayList)context.getAttribute("states");

         ArrayList newStates = new ArrayList();

         String responseText = "";

         //sending response text in the format label:value||label;value

         for(int i=0;i         {

            LabelValueBean temp = (LabelValueBean)states.get(i);

            if(temp.getValue().startsWith(optionSelected))

            {

                    newStates.add(temp); 

                    responseText = temp.getLabel()+";"+temp.getValue()+"||"+responseText; 

            }

         }

         if(responseText.endsWith("||"))   //chop off the ending ||

         {

             responseText = responseText.substring(0, responseText.lastIndexOf("||"));

         }

         PrintWriter out = response.getWriter();

         out.println(responseText);

        //Close the writer

        out.close();

        return(mapping.findForward("content1"));

   }

  }

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CacheServlet.java

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package ajaxsample;



import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.ServletConfig;

import javax.servlet.ServletException;

import java.io.IOException;

import org.apache.struts.util.LabelValueBean;

import java.util.*;

/**

 *

 * @author rupali_l

 */

public class CacheServlet extends HttpServlet {

    

    

    /** Creates a new instance of CacheServlet */

    public void init() throws ServletException {

   

      

        System.out.println("In do get of CacheServlet");

        ArrayList countries = new ArrayList(); 

        countries.add(new  LabelValueBean("India", "1" ));

        countries.add(new  LabelValueBean("U.S","2"));

        countries.add(new  LabelValueBean( "Australia","3"));

        

        ArrayList states = new ArrayList(); 

        states.add(new  LabelValueBean("Maharashtra","11"));

        states.add(new  LabelValueBean( "Delhi","12"));

        states.add(new  LabelValueBean("Goa","13"));

        states.add(new  LabelValueBean( "Newjersey","21"));

        states.add(new  LabelValueBean("NewYork","22"));

        states.add(new  LabelValueBean( "California","23"));

        states.add(new  LabelValueBean("Sydney","31"));

        getServletContext().setAttribute("countries", countries);

        getServletContext().setAttribute("states", states);

        

       

    }

        

    

    public void doGet(HttpServletRequest request ,HttpServletResponse response) throws ServletException,

    IOException

    {

        // request.getRequestDispatcher

    }       

            

    

}

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web.xml

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  Struts Blank Application

  

  

  

    CacheServlet

    ajaxsample.CacheServlet

        1

  



  

  

    action

    org.apache.struts.action.ActionServlet

    

      config

      /WEB-INF/struts-config.xml

    

    

      debug

      2

    

    

      detail

      2

    

    2

  



  

  

    action

    *.do

  





  

  

    index.jsp

  





  

  

    /WEB-INF/struts-bean.tld

    /WEB-INF/struts-bean.tld

  



  

    /WEB-INF/struts-html.tld

    /WEB-INF/struts-html.tld

  



  

    /WEB-INF/struts-logic.tld

    /WEB-INF/struts-logic.tld

  



  

    /WEB-INF/struts-nested.tld

    /WEB-INF/struts-nested.tld

  



  

    /WEB-INF/struts-tiles.tld

    /WEB-INF/struts-tiles.tld

  







struts-config.xml







    

    

                    name="inputForm"

            type="ajaxsample.SampleForm"/>

 

    

    

 

    	name="inputForm" scope="request" validate="false" >
DZone Snippets: dependant code

Dependant Dropdowns Using Ajax
