struts(DWR)

Expert:dileep
i want to pass a combo box value from my jsp page to servlet . where i had to done this by using DWR.. It is getting null value into servlet.

i.e, i am giving my sample code here! plz help me ,

my.jsp::::: jsp page

<html>
<head>
<script type="text/javascript">
var xhr;

function modifyPage() {

try {
xhr = new ActiveXObject("Msxml2.XMLHTTP");
//alert("Msxml2.XMLHTTP ActiveXObject created");
} catch (e) {
try {
xhr = new ActiveXObject("Microsoft.XMLHTTP");
//alert("Microsoft.XMLHTTP ActiveXObject created");
} catch (E) {
xhr = false;
}
}

if (!xhr && typeof XMLHttpRequest != 'undefined') {
xhr = new XMLHttpRequest();
//alert("XMLHttpRequest Object created");
}

xhr.open("GET", "../message", "true");
//alert("Open method called");
xhr.setRequestHeader("User-Agent", "my browser");
//alert("Request header setted");

//here is the actual problem

var queryString ="name=value&anothername=othervalue&so=on";
xhr.send(queryString);

// the values of name and others are getting as "null" in servlet

xhr.onreadystatechange=function()
{
//alert("State : " + xhr.readyState + "" );
if (xhr.readyState != 4) return;
if(xhr.status==200)
{
alert("The document will change now" );
var r=xhr.responseText;
t=r.split(',');
//alert(t);
//document.getElementById("message").innerHTML = xhr.responseText;
//some work on retrieved message. it able to retrieve message here.
}//if
else
{
document.getElementById("items").innerHTML = "ur browser doestnot support ajax";
}
}

xhr.send(null);

}
</script>
</head>
<body>
<form name="form1">

<b>Classes</b>
<input type="text" name="item1" size="45">
<br>
<select name="classes" Id="classes" onChange="modifyPage();">
<option>we</option>
<option>are</option>
<option>here</option>
<option>fru</option>
</select>
<div ID="items">
<input type="hidden" id="add"/>
</div>
<input type="button" value="create"/>
</form>
</body>
</html>

myservlet.java:

import java.io.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.servlet.*;
import javax.servlet.http.*;

public class MessageServlet extends HttpServlet {

private ServletContext context;
private String sub_classes=null;

public void init(ServletConfig config) throws ServletException {
this.context = config.getServletContext();

}

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

response.setContentType("text/plain");
response.setHeader("Cache-Control", "no-cache");

String DriverName = "com.mysql.jdbc.Driver";
String ConnectionURL = "jdbc:mysql://localhost:3306/test";
String UserName = "root";
String Password = "root";

//actual probleh is here

String s=(String)request.getParameter("name");
System.out.println("here see me "+s);

//the above string "s" is printing as null on console of server.
// how to get the value of the name or other variables.here

String Classes_Sale_Display="SELECT * FROM customers where username='"+username+"'";
PreparedStatement pstmt = null;

try {
Class.forName(DriverName);
Connection con = DriverManager.getConnection(ConnectionURL,UserName,Password);
pstmt = con.prepareStatement(Classes_Sale_Display);
ResultSet rs = pstmt.executeQuery ();

while (rs.next())
{
//price=0;
sub_classes =rs.getString("availTraining");
System.out.println(sub_classes);
}
response.getWriter().write(sub_classes);

}//try
catch (Exception e) {
System.out.println(e);
}

}

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {

response.setContentType("text/plain");
response.setHeader("Cache-Control", "no-cache");
response.getWriter().write(sub_classes);

}
}

I am able to pass the control to the servlet through the above code , my only problem here is to get the values from jsp to servlet using xhr.send(); please correct the code and help me

i have been working on it for the last 3 days,

thanks in advance.

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