Error in updating file

Question

Hi im doing project using jsp files.In part of my project there is vote page and vote result page.
my vote_page.jsp
<%@ page import="java.util.*" %>
<%@ page import="java.sql.*" %>
<%@ page import="java.text.*" %>
<%@ page import="java.sql.Date" %>
<%@ page language = "java" %>
<%! int ctr=0;%>
<%! String[] songs=new String[10];%>
<%
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection connect;
connect=DriverManager.getConnection("jdbc:odbc:RegisterDataSource");
Statement state;
state = connect.createStatement();
String strQuery1 = "SELECT title FROM ItemEJBTable";
String str;
ResultSet result1 = state.executeQuery(strQuery1);
while(result1.next())
songs[ctr]=result1.getString("title");
ctr++;
connect.close();
catch(Exception e)
%>
<form method="GET" action="http://localhost:8000/Music/Vote_result_page.jsp">
<p align="center">
<font><b><u>Vote for your favorite song</u></b></font></p>
<font><b>       Songs</b></font>
<font> </font>  
<select size="1" name="Song1">
<%
for(ctr=0;ctr<songs.length;ctr++){
%>
<option>
<% out.println(songs[ctr]);}%>
</option>
</select></td>
</tr>
</table>
<input type="submit" value="Vote" name="submit">and my vote_result_page.jsp
<%@ page import="java.util.*" %>
<%@ page import="java.sql.*" %>
<%@ page import="java.text.*" %>
<%@ page language = "java" %>
<%! int voteNum=0; %>
<%! String selSong=new String();
%>
<% selSong=request.getParameter("Song1");
out.println(selSong);
String selSong1 = selSong.trim().toString();
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection connect;
connect=DriverManager.getConnection("jdbc:odbc:RegisterDataSource");
Statement state,state2;
ResultSet result1;
state = connect.createStatement();
state2 = connect.createStatement();
String strQuery1 = "update Vote_Info set Number_votes=Number_votes+1 where itemCode=(select itemCode from ItemEJBTable where title='"+selSong+"')";
state.executeUpdate(strQuery1);
String strQuery2="select Number_votes from Vote_Info where itemCode = (select itemCode from ItemEJBTable where title='"+selSong1+"')";
result1=state2.executeQuery(strQuery2);
while(result1.next())
voteNum=result1.getInt("NumberVotes");
out.println(selSong+" got "+voteNum+" votes");
connect.close();
voteNum=voteNum+1;
catch(Exception e)
%>
<td width="82%" valign="top">
<!--Display the number of people who have voted for the song-->
<p align="left"><font face="Arial" size="3" color="#800000"><b><u>You voted for the song:</u></b></font>
<p align="left"><font face="Arial" size="3" color="#800000"><b><%=request.getParameter("Song1")%></b></font></p>
<p align="left"><%= voteNum %> <font face="Arial" size="3" color="#800000">people have voted for this song so far.</font></p>
<input type="submit" value="OK" name="submit">When i select song_no_1 and click on vote button on vote_page.jsp it directs to vote result page and displays that
1 person has voted for this song and this vote is not updating on table. When i go again to vote page and vote on song_no_2 it says that "2 person have voted this song" even if it is not voted before.
I dont no where the problem occurs pls help me for this.
hi pls help me..
Edited by: merwyn on Mar 27, 2009 11:03 AM
Edited by: merwyn on Mar 27, 2009 6:44 PM

Answer 1

Sorry, the code is very cluttered and unoverviewable. The motivation to extract all the separate parts/tasks out of the code to allocate your problem is very little. You need to split the code in clear parts each doing its own task independently. This way you can also just debug/test every part independently so that it is more clear where the actual problem lies. Database interaction? Request processing? Request controlling? Data presentation? Configuration settings? Etcetera.
Use a JSP file for pure data presentation only. You can use taglibs/EL to access javabeans in any scope.
Use a Servlet class to process the request, talk with the DAO class, store the data in a scope and forward the request to a JSP file.
Use a DAO class to interact with the database using JDBC and takes/returns the data in javabeans.