The mysteries of JDBC, JNDI, and Tomcat 5.5.4

Question

Like thousands beforefore, I can't get connection pooling to work in Tomcat. I followed all the steps:
- put jar file for MySQL JDBC driver in TOMCAT_HOME/common/lib
- put the Jakarta Commons libs in the same location
- put resource declaration in META-INF/context.xml, per the Tomcat 5.5 docs like so:
<Context docbase="C:\Program Files\Apache Software Foundation\Tomcat 5.5\webapps\commutercorps"
    path="\commutercorps" >
    <Resource name="jdbc/commutercorpsds"
        auth="Container"
        type="javax.sql.DataSource"
        maxActive="100"
        maxIdle="30"
        maxWait="10000"
        username="myusername"
        password="mypassword"
        driverClassName="com.mysql.jdbc.Driver"
        url="jdbc:mysql://localhost:3306/commuter_corps_signup"/>
</Context>- added resource ref in web.xml
    <resource-ref>
        <description>DB Connection</description>
        <res-ref-name>jdbc/commutercorpsds</res-ref-name>
        <res-type>javax.sql.DataSource</res-type>
        <res-auth>Container</res-auth>
    </resource-ref>I also double checked my connection URL and found that it does work fine when do this in my Java code:
Class.forName("com.mysql.jdbc.Driver");
Connection con =
    DriverManager.getConnection
    ("jdbc:mysql://localhost:3306/commuter_corps_signup", "...", "...");When I try to use Tomcat 5.5.4, JNDI like this...
                try
                    InitialContext initialContext = new InitialContext();
                    DataSource dataSource =
                            (DataSource) initialContext.lookup
                            ("java:comp/env/jdbc/commutercorpsds");
                    Connection con = dataSource.getConnection();
                    Statement stmt = con.createStatement();
                    stmt.executeUpdate(SQLMaker.getInsert(request,
                            request.getParameter("table")));
                    con.close();
                    stmt.close();
                } catch (NamingException e)
                    System.out.println(e.getMessage());
                    e.printStackTrace();
                }...I get...
Cannot create JDBC driver of class '' for connect URL 'null'
Caused by: java.sql.SQLException: No suitable driver
Any help would be greatly appreciated.
Thanks,
E

Answer 1

I used to get the message
Cannot create JDBC driver of class '' for
connect URL 'null'
No suitable driverError.
I was running, jakarta-tomcat-5.0.14.exe on windows.
I had it installed on a path without spaces
d:\tomcat5\Good.
I wanted to use Hibernate. So i used, extensiontools.What's that?
First create a env var: HIBERNATE_HOME pointing to
the hibernate extracted dir.No need for this.
Modify setenv.bat to correct %CP% for
commons-logging, commons-collection and anything
else: the version string at the end of the jar
changes.Wrong. You shouldn't be doing this.
Then run ddl2hbm, straightforward, fill info in all
tabs and hit generate. Will show some error message,
but still creates xmls.I don't see what any of this has to do with Tomcat deployment.
Then run hbm2java, and hand over each xml file as
parameter. Creates some java files in generated dir.
Modify the toString method to something simpler and
remove the import for apache class.All great, but still has nothing to do with Tomcat deployment.
move them over to webapp classes.You should create a WAR file or a separate context directory for your application under /webapps. If you're doing anything else, it's wrong.
Create JNDI in sever.xml as mentioned.Nope. Shouldn't be editing server.xml. Put that stuff in an application-specific context.xml, which goes in the META-INF of your WAR file.
Create reference in web.xml as mentioned.Good.
Goto conf/catalina/localhost/<webappname>.xmlNo need for this. Don't know what you're doing here.
add the line
<ResourceLink name="jdbc/Oracle"
type="javax.sql.DataSource" global="jdbc/Oracle"/>
replace Oracle with your datasource name.
and i got me workingMight be working, but it's not really correct.
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