[opencms-dev] nested SQL Exception if connection pool
Jordi Martí
jmarti at theinit.com
Fri Feb 29 18:34:25 CET 2008
> With your suggested solution a connection is made everytime the page is
invoked
Thats the way it should be. It's the "normal" way of doing it in "normal"
applications (j2ee, php, etc.)
If you gave a connection to each session, your database pool would be
exhausted soon.
JORDI MARTÍ
Email: jmarti at theinit _dot_ com
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-----Mensaje original-----
De: opencms-dev-bounces at opencms.org [mailto:opencms-dev-bounces at opencms.org]
En nombre de Christoph P. Kukulies
Enviado el: viernes, 29 de febrero de 2008 18:16
Para: The OpenCms mailing list
Asunto: Re: [opencms-dev] nested SQL Exception if connection pool
Thanks. My initial concern was about the lifetime of a connection.
With your suggested solution a connection is made everytime the
page is invoked. Is it the way db apps are normally written?
Or can the connection be kept over the session?
--
Chris Christoph P. U. Kukulies kukulies (at) rwth-aachen.de
On Fri, Feb 29, 2008 at 05:48:31PM +0100, Jordi Mart? wrote:
> Wops, my bad:
>
> Connection c;
> Statement st;
> ResultSet rs;
> try {
> c=getSqlManager()......;
> st=c......
> rs=st....
> }
> catch (Exception e) {
> e.printStackTrace();
> }
> finally {
> rs.close();
> st.close();
> c.close();
> }
>
> (this is an ugly example, you should do some exception checking, some
> logging, create managers and dao classes to do all this stuff,
blablablabla,
> ok?).
>
>
>
> JORDI MARTÍ
> Skype id: jmarti.theinit
>
>
>
> -----Mensaje original-----
> De: opencms-dev-bounces at opencms.org
[mailto:opencms-dev-bounces at opencms.org]
> En nombre de Christoph P. Kukulies
> Enviado el: viernes, 29 de febrero de 2008 17:31
> Para: The OpenCms mailing list
> Asunto: Re: [opencms-dev] nested SQL Exception if connection pool
>
> On Fri, Feb 29, 2008 at 04:46:00PM +0100, Jordi Mart? wrote:
> > Do you free statements and close connections?
> >
> > try {
> > Connection c=getSqlManager()......;
> > ResultSet rs=c....
> > }
> > catch (Exception e) {
> > e.printStackTrace();
> > }
> > finally {
> > rs.close();
> > c.close();
> > }
>
> I'm getting
> An error occurred at line: 88 in the jsp file:
>
/WEB-INF/jsp/offline/system/modules/org.yaml.frontend/templates/yamlmain.jsp
> rs cannot be resolved
> 85: e.printStackTrace();
> 86: }
> 87: finally {
> 88: rs.close();
> 89: c.close();
> 90: }
> 91: %>
>
> An error occurred at line: 89 in the jsp file:
>
/WEB-INF/jsp/offline/system/modules/org.yaml.frontend/templates/yamlmain.jsp
> c cannot be resolved
> 86: }
> 87: finally {
> 88: rs.close();
> 89: c.close();
> 90: }
> 91: %>
> 92: </div>
>
>
> Here is my template code:
>
> <%@page
import="org.opencms.jsp.*,org.opencms.file.*,java.util.*,java.sql.*"
> %>
> <%@ taglib prefix="cms" uri="http://www.opencms.org/taglib/cms" %>
> <%@ taglib prefix="fmt" uri="http://java.sun.com/jstl/fmt" %>
> <%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
>
> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
> "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
>
> <cms:template element="head" >
> <cms:include file="../elements/yamlhead" element="head"/>
> </cms:template>
> <div id="main">
> <div id="col1">
> <div id="col1_content" class="clearfix">
> <!-- add your content here -->
> <%
> CmsJspActionElement jsp = new CmsJspActionElement(pageContext,
> request,response);
>
> String konto=request.getParameter("konto");
> String tmp,item,desc,id;
>
> try {
> java.sql.Connection c =
>
> org.opencms.main.OpenCms.getSqlManager().getConnection("application");
> java.sql.Statement st = c.createStatement();
> java.sql.ResultSet rs = st.executeQuery("select id,name from
> konten");
> java.sql.ResultSetMetaData md = rs.getMetaData();
> out.println("\n<ul>");
> while(rs.next()) {
> out.println("\n<li>");
> for(int i=1; i<= md.getColumnCount(); i++) {
> item=rs.getString(i);
> tmp = "<a
> href=\"/opencms/opencms/sites/kuku/index.html?konto=" +item + "\" >"+
> item + "</a>";
>
> if(tmp == null)
> tmp=" ";
> out.println( tmp );
> }
> out.println("</li>");
> }
> out.println("</ul>");
>
> %>
>
> </div>
> </div>
> <div id="col2">
> <div id="col2_content" class="clearfix">
> <!-- add your content here -->
>
>
>
> </div>
> </div>
> <div id="col3">
> <div id="col3_content" class="clearfix">
> <!-- add your content here -->
> <%
>
> if(( id=request.getParameter("konto"))!=null){
> rs = st.executeQuery("select * from buchung where
> konto="+id);
> ;
> out.println("\n<ul>");
> md = rs.getMetaData();
> while(rs.next()) {
> out.println("\n<li>");
> for(int i=1; i<= md.getColumnCount(); i++) {
> item=rs.getString(i);
>
> tmp = item ;
> if(tmp == null)
> tmp=" ";
> out.println( tmp );
> }
> out.println("</li>");
> }
>
> out.println("</ul>");
> } else { out.println("<h2>Set empty</h2>"); }
> } catch (Exception e) {
> e.printStackTrace();
> }
> finally {
> rs.close();
> c.close();
> }
> %>
> </div>
> <!-- IE Column Clearing -->
> <div id="ie_clearing"> </div>
> </div>
> </div>
> </div>
> </div>
> </body>
> </html>
>
> >
> >
> >
> > JORDI MARTÍ
> > Email: jmarti at theinit.com
> > Tlfno: 944.01.50.40 - Fax: 944.153.424
> > Móvil: 605.41.82.93
> > Skype ID: jmarti.theinit
> >
> >
> >
> >
> >
> >
> --
> Chris Christoph P. U. Kukulies kukulies (at) rwth-aachen.de
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