dynamic drop down list box

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September 22, 2008 at 12:57 PM

At first u decide, u use servlet ot not, bcoz servlet comes under server side code.

if not using servlet store the all data inside a javascript file.

if u use servlet there might be chance of loss previous displayed data.

for overcome this situation you can use AJAX.

Thanks
Rajanikant

September 22, 2008 at 6:37 PM

Hi friend,

<%@ page language="java" import = "java.util.*;"%>
<%
List userList;
int nouser;
int i=1;
List cityList;
int nocity;
int j=1;
%>
<%
userList=(ArrayList)request.getAttribute("useridList");
nouser = userList.size();
%>

<%
cityList=(ArrayList)request.getAttribute("cityList");
nocity=cityList.size();
%>
<html>
<head>
<title>dynamic bombobox in servlet</title>
</head>
<body>
<br><br>
<center>
<table border="1" width="300px" bgcolor="bluelight" cellspacing="0" cellpadding="0">
<tr>
<td width="100%">
<form method="GET" action="/examples/jsp/ComboboxList">
<font color="red"><h3 align="center">Dynamic Combobox List</font></h3>
<table border="1" width="300px" cellspacing="0" cellpadding="0">
<tr>
<td width="50%"><b>User Name:</b></td>
<td width="50%"><select name="userid" value="">
<option value="0">---Select Name---</option>
<%
Iterator userit= userList.iterator();
while(userit.hasNext()){
while(i<=nouser){%>
<option value="<%=i%>"><%=userit.next()%></option>
<%
i++;
}
}
%>
</select>
</td>
</tr>
<tr>
<td width="50%"><b>City:</b></td>
<td width="50%">
<select name="city" value="">
<option value="0">----Select city----</option>
<%
Iterator cityit= cityList.iterator();
while(cityit.hasNext()){
while(j<=nocity){%>
<option value="<%=j%>"><%=cityit.next()%></option>
<%
j++;
}
}
%>

</select>

</td>
</tr>

</table>

</form>
</td>
</tr>
</table>
</center>
</body>

</html>

September 22, 2008 at 6:38 PM

servlets code

package javacode;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
import java.util.*;
import java.util.ArrayList;

public class ComboboxList extends HttpServlet{
public void doGet(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException{
response.setContentType("text/html");
PrintWriter pw = response.getWriter();
Connection con = null;
String url = "jdbc:mysql://192.168.10.211:3306/";;
String db = "amar";
String driver = "com.mysql.jdbc.Driver";
String userName ="amar";
String password="amar123";
try{
Class.forName(driver);
con = DriverManager.getConnection(url+db,userName,password);
Statement st = con.createStatement();
ResultSet rs = st.executeQuery("select * from Combolist");
List ulist = new ArrayList();
List clist = new ArrayList();
while(rs.next()){
request.setAttribute("userid", rs.getString(2));
request.setAttribute("city", rs.getString(3));
pw.println("userid" + " "+"city"+"<br>");
pw.println(rs.getString(2) + " " + rs.getString(3) +"<br>");
ulist.add(rs.getString(2));
clist.add(rs.getString(3));

}
request.setAttribute("useridList", ulist);
request.setAttribute("cityList", clist);
}
catch (Exception e){
pw.println(e);
}
RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/jsp/Combobox.jsp");
dispatcher.forward(request, response);
}

}

September 22, 2008 at 6:40 PM

web.xml

<servlet>
<servlet-name>comboboxList</servlet-name>
<servlet-class>javacode.ComboboxList</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>comboboxList</servlet-name>
<url-pattern>/jsp/ComboboxList</url-pattern>
</servlet-mapping>

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

Read for more information.

http://www.roseindia.net/servlets/

Thanks.

Amardeep.

dynamic drop down list box

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