tomcat connection pooling

[pooja jain]

i am using mysql db.

here is what i am doing:

1. following entries in server.xml:

    
 
inside global naming resources tag:
 
<Context path="/dbcp" docBase="dbcp" debug="5"
      reloadable="true" crossContext="true">
      
      <Resource name="jdbc/TestDB" auth="Container"
         type="javax.sql.DataSource" removeAbandoned="true"
         removeAbandonedTimeout="30" maxActive="100"
         maxIdle="30" maxWait="10000" username="admin"
         password="admin"
         driverClassName="com.mysql.jdbc.Driver"
         url="jdbc:mysql://localhost/dbcptest"/>
      
</Context>
 
inside <Service name="Catalina"> tag:
 
<Connector port="80" maxHttpHeaderSize="8192" maxProcessors="150"
     maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
     enableLookups="false" redirectPort="8443" acceptCount="150"
   connectionTimeout="20000" disableUploadTimeout="true" />

2. folling code in my context listener:

   
public void contextInitialized(ServletContextEvent sce){
 
  try {
 

System.out.println("context listener is called...");
 

    // Obtain our environment naming context
    Context envCtx = (Context) new InitialContext().lookup("java:comp/env");
 
    // Look up our data source
    DataSource  ds = (DataSource) envCtx.lookup("jdbc/TestDB");
 
System.out.println("data source --> " + ds);
 
    Connection con = ds.getConnection();
 

System.out.println("connection --> " + con);
 
   } catch(Exception e){ e.printStackTrace();
  }
 }
 
 

when i start the server, i get following exception:

 
SQLNestedException: Cannot create JDBC driver of class '' for connect URL 'null'
 

i follow following link: http://www.onjava.com/pub/a/onjava/2006/04/19/database-connection-pooling-with-tomcat.html?page=2

please help.

[Ben Souther]

Where did you put your JDBC driver?

[Ben Souther]

Also, instead of using the onJava article, why aren't you using the current Tomct documentation for the version of Tomcat that you're running?

I don't know how old that article is but the Tomcat documentation has advised against putting <Context .../> entries in server.xml since version 5.0.

[pooja jain]

Originally posted by Ben Souther:
Where did you put your JDBC driver?

i keep it (mysql.jar) into lib folder of tomcat.

[pooja jain]

Originally posted by Ben Souther:
Where did you put your JDBC driver?

i keep it (mysql.jar) into lib folder of tomcat.

[pooja jain]

Originally posted by Ben Souther:
Also, instead of using the onJava article, why aren't you using the current Tomct documentation for the version of Tomcat that you're running?

I don't know how old that article is but the Tomcat documentation has advised against putting <Context .../> entries in server.xml since version 5.0.

okay. its mentioned. and it can be mentioned at following places:

    
Context elements may be explicitly defined: 
 
in the $CATALINA_HOME/conf/context.xml file: the Context element information will be loaded by all webapps 
in the $CATALINA_HOME/conf/[enginename]/[hostname]/context.xml.default file: the Context element information will be loaded by all webapps of that host 
in individual files (with a ".xml" extension) in the $CATALINA_HOME/conf/[enginename]/[hostname]/ directory. The name of the file (less the .xml) extension will be used as the context path. Multi-level context paths may be defined using #, e.g. context#path.xml. The default web application may be defined by using a file called ROOT.xml. 
if the previous file was not found for this application, in an individual file at /META-INF/context.xml inside the application files 
inside a Host element in the main conf/server.xml 
 

1. context.xml already have a context element. should i replace it?
2. in 2nd and 3rd option, there is no engine name and host name folder in my system.
3. in 4th, i dont have META-INF folder in my application.
4. in 5th, isn't it modifying host tag is equivalent to modifying context tag? both are common for all application deployed on this tomcat.

[pooja jain]

inside a Host element in the main conf/server.xml

now i placed context tag inside host tag of server.xml file but still the same error.

[Ben Souther]

My point was that you'd be better off using the documentation on the Tomcat site; especially if you use the one that is matched to the exact version of Tomcat that you're using.

If something changed since that magazine article was written, it will throw you off.

[pooja jain]

Originally posted by Ben Souther:
My point was that you'd be better off using the documentation on the Tomcat site; especially if you use the one that is matched to the exact version of Tomcat that you're using.

If something changed since that magazine article was written, it will throw you off.

i understood. now i am referring tomcat site but still the same error.

[Pushkal Mishra]

Pooja,

I take it that you have also modified the necessary element in web.xml (<resource-ref>).

Thanks,
Pushkal

Originally posted by pooja jain:


okay. its mentioned. and it can be mentioned at following places:

    
Context elements may be explicitly defined: 
 
in the $CATALINA_HOME/conf/context.xml file: the Context element information will be loaded by all webapps 
in the $CATALINA_HOME/conf/[enginename]/[hostname]/context.xml.default file: the Context element information will be loaded by all webapps of that host 
in individual files (with a ".xml" extension) in the $CATALINA_HOME/conf/[enginename]/[hostname]/ directory. The name of the file (less the .xml) extension will be used as the context path. Multi-level context paths may be defined using #, e.g. context#path.xml. The default web application may be defined by using a file called ROOT.xml. 
if the previous file was not found for this application, in an individual file at /META-INF/context.xml inside the application files 
inside a Host element in the main conf/server.xml 
 

1. context.xml already have a context element. should i replace it?
2. in 2nd and 3rd option, there is no engine name and host name folder in my system.
3. in 4th, i dont have META-INF folder in my application.
4. in 5th, isn't it modifying host tag is equivalent to modifying context tag? both are common for all application deployed on this tomcat.