• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other Pie Elite all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Paul Clapham
  • Ron McLeod
  • Jeanne Boyarsky
  • Tim Cooke
Sheriffs:
  • Liutauras Vilda
  • paul wheaton
  • Henry Wong
Saloon Keepers:
  • Tim Moores
  • Tim Holloway
  • Stephan van Hulst
  • Carey Brown
  • Frits Walraven
Bartenders:
  • Piet Souris
  • Himai Minh

problem with resultset in reference with my previous post

 
Ranch Hand
Posts: 185
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi All!!
Thanks for ur concern in solving out my query.
as u asked for the code, i don't know how best i can represent it to u, as it's very easy easy to get confused with the project specific intricacies & database details.
one or two three things i would like to tell u
1. i don't what do u mean by thread safe sevlet or jsp page for that metter (and i only know that web server takes care of it by itself.)
2. i haven't closed my resultset object anywhere in the whole file as if i go about doing that then tomcat causes even more problem.
i mean i haven't used the folowing code anywhere in the file
resultset1.close();
resultset2.close();
statement1.close();
statement1.close();
conn.close();
now here is my code sample............................
ur help is very much required....
Thanks in advance
lusha

<%response.setContentType("text/html");<br /> response.setDateHeader("Expires",0);<br /> response.setHeader("Cache-Control","no-cache");<br /> response.setHeader("Pragma","no-cache");<br /> %>

<%@ page language='java' import='java.sql.*,javax.servlet.*,javax.servlet.http.*,java.io.*,java.sql.*,java.util.*' %><br /> <HTML><br /> <HEAD><br /> </HEAD><br /> <%<br /> HttpSession mysession=request.getSession(true);<br /> String user_type= (String)mysession.getValue("ut");<br /> //the following code checks for the vaidity of session<br /> if(mysession.isNew()| |(user_type==null))<br /> {<br /> //if invalid print "u have already logged out" on the terminal<br /> %><br /> <body bgcolor="#CCCC99" text="#333300" topmargin="0" leftmargin="0" marginheight=0 marginwidth=0 link="#FFFFFF" vlink="#FFFFFF"><br /> <br /> <br /> <center><h4>You have already logged out !</h4></center><br /> </body><br /> </html><br /> <%<br /> mysession.invalidate();<br /> }<br /> else<br /> {<br /> //if valid session do the folowing procesing<br /> %><br /> <body bgcolor="#CCCC99" text="#333300" topmargin="0" leftmargin="0" marginheight=0 marginwidth=0 link="#FFFFFF" vlink="#FFFFFF"><br /> <FORM name="frm" METHOD=POST ACTION="/ExamEngine/eval_paper.jsp"><br /> <%! <br /> //database objects declarations<br /> Connection conn=null;<br /> ResultSet resultset1=null;<br /> ResultSet resultset2=null;<br /> Statement statement1=null;<br /> Statement statement2=null;<br /> //other instance variable declarations such as<br /> String exam_cand_id;<br /> %><br /> <%<br /> //get value from session variable such as<br /> exam_cand_id = (String)mysession.getValue("exam_cand_id");<br /> %><br /> <br /> <%<br /> //database connection code<br /> <br /> Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");<br /> conn=DriverManager.getConnection("jdbc dbc:ex_eng", "sa", "");<br /> statement1=conn.createStatement();<br /> statement2=conn.createStatement();<br /> <br /> //here some update statemnet with statement object "statement1"<br /> //here some select query statemnt with "statement1","resultset1"<br /> //retreiving values from "resultset1"<br /> //here some update statemnet with statement object "statement1"<br /> //here some select query statemnt with "statement1","resultset1"<br /> //retreiving values from "resultset1"<br /> //here some select query statemnt with "statement2","resultset2"<br /> //value retrieval from "resultset2"<br /> <br /> <br /> %><br /> <%<br /> }//end of else<br /> %>
 
Ranch Hand
Posts: 1879
MySQL Database Suse
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
lusha:
I could see your code when I went to reply to you. To make your code visible you have to take the html stuff out and just post the java code. I think I see your problem. you are using the jdbc dbc bridge. There are some restrictions when you use this driver. One of them is that you can only have one statement per connection. I see that you have 2 statements for 1 connection. When you open the second statement, you are implicitly closing the first statement(and again implicitly closing any associated resultsets to the first statement). You are limited to one statement per connection, so you need to open another connection to exececute the second statement.
Jamie
 
Jamie Robertson
Ranch Hand
Posts: 1879
MySQL Database Suse
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
here are some jdbc dbc FAQ's: http://java.sun.com/products/jdbc/faq.html

and specifically for your problem: http://java.sun.com/products/jdbc/faq.html#21
Jamie
 
Brace yourself while corporate america tries to sell us its things. Some day they will chill and use tiny ads.
free, earth-friendly heat - a kickstarter for putting coin in your pocket while saving the earth
https://coderanch.com/t/751654/free-earth-friendly-heat-kickstarter
reply
    Bookmark Topic Watch Topic
  • New Topic