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Struts

reponseXML empty Ajax/Struts

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Posts: 180

posted 17 years ago

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Hi all,

Posting again..I am doing a double combo box with Ajax on Struts. I have all things in place..(I believe so) but i cant get the output on the JSP... Struts 1.2.9, JDK 1.4.
I had SOPs in the Class and I get the structure of the XML correct as made by the class. Ive checked out Merrill's link and made all necessary changes. Even Eric helped me some network error, but i cant seem to get the response on the JSP.. On IE the readyState goes on like 1-2-3-4. and it goes in the Loop for the reponse. But XRows.length returns 0. Dunno y??? PLEASE help...
------------------
Index.jsp
----------

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
 
    <title>Double Combo - Ajax In Action</title>
  <script>
 
/*Data retrieval for selected feature*/
var reqFeature;
function  FillTerritory() {
var strValue=document.inputForm.ddlRegion.options[document.inputForm.ddlRegion.selectedIndex].value;
alert('The strValue is: '+strValue);
url="SecondOptionsAction.do?type="+strValue;

if (window.XMLHttpRequest) { // Non-IE browsers
reqFeature = new XMLHttpRequest();
try{
reqFeature.open("GET", url, true);
} 
catch (e) {
alert(e);
}
reqFeature.onreadystatechange = processStateChangeFeature;
reqFeature.send(null);
} 
else if (window.ActiveXObject) { // IE
 
reqFeature = new ActiveXObject("Microsoft.XMLHTTP");
 
if (reqFeature) {

reqFeature.open("GET", url, true);
reqFeature.onreadystatechange = processStateChangeFeature;
reqFeature.send(null);
}
}
}
 
function processStateChangeFeature() 
{
var status;
try{
status=reqFeature.status;
alert('In the callback and the readyState is:'+reqFeature.readyState);
if (reqFeature.readyState == 4) 
{ // Complete
alert('I shouldnt be here');
if (reqFeature.status == 200) 
{ // OK response
alert('Checking HTML response');
xml = reqFeature.responseXML;
alert('I have the response'+xml);
var xRows = xml.getElementsByTagName("entry");
alert('Value of XRows:'+xRows);
alert('Value of Xrows:'+xRows.length);

for(i=0;i<xRows.length;i++)
{     
alert('Im looping through the elements');
  var theText = xRows[i].childNodes[0].firstChild.nodeValue;
                                                  var theValue = xRows[i].childNodes[1].firstChild.nodeValue;
                                                  var option = new Option(theText,theValue);                           
      objDDL.options.add(option,objDDL.options.length);
} 
}
} 
else {
alert("Problem: " + reqFeature.statusText);
}
 
 
 
}
catch(e)
{
status="Not found";
}

}

</script>
     
  <body>
    <form name="inputForm" method="post" action="/SecondOptionsAction" id="inputForm">
      <select name="ddlRegion" onchange="javascript:FillTerritory()" id="Select1"><option value="-1">Pick A Region</option>
        <option value="1">Eastern</option>
        <option value="2">Western</option>
        <option value="3">Northern</option>
        <option value="4">Southern</option></select>
      <select name="ddlTerritory" id="Select2"></select>
    </form>
  </body>
</html>

--------------------

SecondOptionsAction.java
-------

package com.abc;
import org.apache.log4j.*;
import com.cris.ResultBean;
 
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionError;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
 
import java.io.*;
 
import java.util.*;
import java.sql.*;
import java.sql.Connection;
 
import javax.servlet.http.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
 
public class SecondOptionsAction extends Action
  {
   public ArrayList fillDataTable(String sqlQuery ) 
{
ArrayList results= new ArrayList();
ResultSet rs=null;
Connection con=null;
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
con=DriverManager.getConnection("jdbc:odbc:ankitDB1","scott","tiger");
Statement st=con.createStatement();
rs= st.executeQuery(sqlQuery);
while (rs.next())
{
//ArrayList results= new ArrayList();

ResultBean resultBean = new ResultBean();

String tDesc=rs.getString("TerritoryDescription");
resultBean.setTerritoryDescription(tDesc);
String tID=rs.getString("TerritoryID");
resultBean.setTerritoryID(tID);
results.add(resultBean);
}
}
catch(Exception e)
{
System.out.println("Exception "+e);
}
finally
{
if (rs != null)
{
/*
Statement stmt = rs.getStatement();
if (stmt != null)
{
stmt.close();
}
*/
//rs.close();
//con.close();
}
}
return results;
}
 
      public ActionForward execute(ActionMapping mapping, ActionForm form,
        HttpServletRequest request, HttpServletResponse response)
        throws IOException, ServletException
      {

response.setContentType("text/xml");
//response.setHeader("Cache-Control", "no-cache");
String type=request.getParameter("type");
String strSql = "SELECT TerritoryDescription,TerritoryID FROM Territories" 
+ " WHERE regionid ='" + type +"' ORDER BY TerritoryDescription";
 
ArrayList dtOptions=new ArrayList();
dtOptions=fillDataTable(strSql);
Iterator iterator=dtOptions.iterator();
 
if(iterator!=null) 
{
ResultBean rb = new ResultBean();
String strForm="inputForm";
String strElem="ddlTerritory";
 
StringBuffer strXML= new StringBuffer("<?xml version=1.0 ?>");
strXML.append("<selectChoice>");
strXML.append("<selectElement>");
strXML.append("<formName>"+strForm+"</formName>");
strXML.append("<formElem>"+strElem+"</formElem>");
strXML.append("</selectElement>");
strXML.append("<entry>");
strXML.append("<optionText>Select A Territory</optionText>");
  strXML.append("<optionValue>-1</optionValue>");
strXML.append("</entry>");

while(iterator.hasNext())
{
rb = (ResultBean) iterator.next();
String terr_description = rb.getTerritoryDescription();
String terr_id=rb.getTerritoryID();
 
strXML.append("<entry>");
strXML.append("<optionText>"+terr_description
+"</optionText>");
strXML.append("<optionValue>"+terr_id
+"</optionValue>");
strXML.append("</entry>");
}
strXML.append("</selectChoice>");
PrintWriter out = response.getWriter();
out.println(strXML);
out.flush();
  }
  
        return null;
}
  }

------------------
struts-config.xml...
-------

-----------------------
I dont understand where I am doing wrong... Any help would be appreciated..

Regards,
Roshani

[ September 13, 2006: Message edited by: RoshaniG Gopal ]
(Added code UBB tags)
[ September 14, 2006: Message edited by: Merrill Higginson ]

Regards,<br />Roshani

Anay Nayak

Greenhorn

Posts: 26

posted 17 years ago

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Well i can see two errors...

1)StringBuffer strXML= new StringBuffer("<?xml version=1.0 ?>"); the value 1.0 shoud be in quotes. new StringBuffer("<?xml version=\"1.0\" ?>");

2) You have not defined objddl variable

RoshaniG Gopal

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Posts: 180

posted 17 years ago

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Hi Anay,

Thanks a lot... Well your effort has helped me do the ajax implementation sucessfully..

Thanks again...

Cheers!!
Roshani

Regards,<br />Roshani

Merrill Higginson

Ranch Hand

Posts: 4864

posted 17 years ago

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I haven't examined your code thoroughly, and couldn't tell you exactly what's wrong, but here are a few thoughts:

1- I'd suggest you actually create the second select box without any options in the first JSP rather than trying to build it from scratch in JavaScript. If you don't want it to be seen, you can easily use CSS to hide it (style="visibility:hidden") and then make it visible after the AJAX call. If you do it this way, you only have to worry about populating the options.

2- If you read my post referred to above, you should also note the comments I made about the responseText property vs. the responseXML property. The rule is, if you don't have perfectly formatted XML, the responseXML will be blank, and the responseText property will have the value. If you're not real familiar with JavaScript's XML parsing functions, you might be better off sending plain text and using String functions to parse through it.

3- Even though I've written a lot of dependent select boxes, I've done all mine using the DWR framework, which I find much easier to implement than writing the AJAX calls and parsing the data myself.

4- Here is a link to a BLOG entry of someone's code who is doing exactly what you're trying to do. You may find it helpful.

5- Good luck!

Merrill
Consultant, Sima Solutions

RoshaniG Gopal

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Posts: 180

posted 17 years ago

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Hi Merrill,
Thanks a lot for your inputs. I wanted to use ResponseXML as the client wanted to do so...(reasons??).
And yes, I read all your inputs on all the topics..Its so nice of you and all others who spare their precious time and give valuable suggestions.

I had already checked the link to the blog that you referred to. But of all the links that I found on net were either incomplete ( they were pointers to the way to do it) or they were on .NET. For a person like me, who understands little of .NET/VB the material was of little use.Plus none of them was on Struts framework with interaction with the DB.

Now that i have implemented it, I would like to give that code so that it may be put on javaranch and anybody else may be able to use it straight away. If you feel it would help people, i can post the working code.

Regards,
Roshani.

Regards,<br />Roshani

Pandu Rangam

Greenhorn

Posts: 24

posted 16 years ago

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Hi,
This is very useful information.
Thanks a lot

SCJP 1.4,<br />SCWCD 1.4