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From Eddie Bush <ekb...@swbell.net>
Subject Re: db connections and Abusive refresh
Date Thu, 02 May 2002 15:47:40 GMT
Use MVC - Struts works good.  Make life easier on yourself.

http://jakarta.apache.org/struts/index.html

----- Original Message -----
From: "Laurent FĂ©ral-Pierssens" <laurent-lists@distincthorizon.com>
To: "'Tomcat Users List'" <tomcat-user@jakarta.apache.org>; <gjk@qwest.net>
Sent: Thursday, May 02, 2002 10:41 AM
Subject: RE: db connections and Abusive refresh


>
> Jay,
>
> From what we do in the page, it is hardly possible to actually do that.
> But we'll try to make some example and compare both methods.
>
> Thanks,
> Laurent
>
>
> -----Original Message-----
> From: Jay Gardner [mailto:gjk@qwest.net]
> Sent: May 1, 2002 6:33 PM
> To: Tomcat Users List; Jacob Kjome
> Subject: RE: db connections and Abusive refresh
>
>
> If you are not going to use MVC is there any reason why you can't do
> your database accesses at the top of your JSP and the put the results in
> variables to be output below in the page? Sorry, if I don't understand
> your question, but it sounded like you were holding a database
> connection open until a scriplet closes it at the bottom of the page.
>
> --JG
>
> -----Original Message-----
> From: Jacob Kjome [mailto:hoju@visi.com]
> Sent: Wednesday, May 01, 2002 1:31 PM
> To: Tomcat Users List
> Subject: Re: db connections and Abusive refresh
>
> Hello Laurent,
>
> Yes,
>
> Here is an example.  Take notice of how connections, result sets, and
> prepared statements are guaranteed to be closed in the "finally"
> blocks:
>
>
> public Site getSite( int _id ) throws SQLException
>     {
>         Connection conn = null;
>         Site newSite    = null;
>
>         try {
>             conn = openConn();
>             newSite = getSite(_id, conn);
>             closeConn(conn);
>             return newSite;
>         }
>         catch(SQLException e) {
>             System.out.println(MSG_ERROR_CONNECTION + e.getMessage());
>             throw e;
>         }
>         finally {
>             if (conn != null)  try { closeConn(conn); } catch(Exception
> e2) {}
>         }
>     }
>
>     //  Get a single site by id
>     public Site getSite( int _id, Connection _conn ) throws SQLException
>     {
>         PreparedStatement pstmt = null;
>         ResultSet rs = null;
>         Site newSite = null;
>
>         String query = "SELECT id, url, description, created, updated,
> deleted " +
>                        "FROM site WHERE id = ?";
>
>         try {
>             pstmt = _conn.prepareStatement(query);
>             pstmt.setInt(1,_id);
>             rs = pstmt.executeQuery();
>
>             while (rs.next()) {
>                 newSite = Site.fromResults(rs);
>                 if (debug) System.out.println("\n" + newSite);
>             }
>             rs.close();
>             pstmt.close();
>             return newSite;
>         }
>         catch(SQLException e) {
>             System.out.println(MSG_ERROR_RESULTSET + e.getMessage());
>             throw e;
>         }
>         finally {
>             if (rs != null)    try { rs.close(); }    catch(Exception
> e2) {}
>             if (pstmt != null) try { pstmt.close(); } catch(Exception
> e3) {}
>         }
>     }
>
>
> You can also use Syncronization if it is still a problem.
>
> Jake
>
> Wednesday, May 01, 2002, 2:23:17 PM, you wrote:
>
>
> LFP> Hi all,
>
> LFP> We are experiencing a few problems with our DB connection code and
> LFP> an abusive usage of the F5/refresh function on the client side.
>
> LFP> Each of our jsp actually connects to the db at the top and
> LFP> disconnects at the bottom. When someone uses the refresh in the
> LFP> browser it leaves connections hanging/sleeping in MySQL. Is there
> LFP> anyway to avoid this?
>
> LFP> Thanks for the help,
> LFP> Laurent
>
>
>
>
> LFP> --
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>
>
> --
> Best regards,
>  Jacob                            mailto:hoju@visi.com
>
>
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