Re: Exception when trying to configure a pool of connections for use of WS

[David Smith]

Oops!  I goofed in adapting the docs example.  The code yours should 
look like is below.  Oddly enough, the mistake I made in my previous 
post would have caused the error you were asking about.

--David
David Smith wrote:
This isn't the code I was asking for.  You should have some code that 
looks up the DataSource via JNDI (javax.naming.* classes).  Following 
the examples in the tomcat docs, it would look like:

Context initContext = new InitialContext();
DataSource ds = 
(Datasource)initContext.lookup("java:/comp/env/jdbc/MySQL_cellmlrep");
Connection conn = ds.getConnection();
... on to doing some work here ...

--David

Daniele Development-ML wrote:
Thanks David!
The code is:

Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/cellmlrep";

Connection con = DriverManager.getConnection(url, "root", "");

Statement stmt = con.createStatement();

String query = "SELECT * FROM user_accounts u;";
stmt.executeQuery(query);


Daniele

On Fri, Sep 5, 2008 at 6:00 PM, David Smith <[EMAIL PROTECTED]> wrote:

 
And the code you use to get a connection?  Looks like the database pool
should be fine, you are getting a javax.sql.DataSource object but 
treating
it as a java.naming.Context object.

As an aside and definitely not things affecting the issue you describe
below:
1. Do not use the root user in the database service for a web 
application.
 It's a potential security flaw big enough to fit a jumbo jet into.
2. Do use strong passwords on the database (especially for the root
account) with at least three character classes (upper case, lower case,
punctuation, numbers) and no dictionary words present.
2. Add a validatonQuery="select 1" attribute to your <Resource ... />
element so connections are tested and regenerated as needed.

--David


Daniele Development-ML wrote:

   
Hello everybody,

I am trying to set up the configuration for a pool of connections to a
MySQL
DB and I get the following exception when deploying on Tomcat.
I followed the steps at

http://tomcat.apache.org/tomcat-6.0-doc/jndi-datasource-examples-howto.html 

.

The application actually consists of a web service that performs a 
query
to
the DB.

Any hints or suggestions? Thank you!

Context file

<?xml version="1.0" encoding="UTF-8"?>
<Context path="/DB_WS" debug="5" reloadable="true" 
crossContext="true">
   <Resource name="jdbc/MySQL_cellmlrep" type="javax.sql.DataSource"
auth="Container"
             user="root" password="root"
driverClassName="com.mysql.jdbc.Driver"
             url="jdbc:mysql://localhost:3306/cellmlrep" maxActive="8"
maxIdle="4"/>
</Context>

Web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee";
xmlns:xsi="
http://www.w3.org/2001/XMLSchema-instance"; xsi:schemaLocation="
http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd";>
   <listener>


<listener-class>com.sun.xml.ws.transport.http.servlet.WSServletContextListener</listener-class> 

   </listener>
   <servlet>
       <servlet-name>DBAccess</servlet-name>


<servlet-class>com.sun.xml.ws.transport.http.servlet.WSServlet</servlet-class> 

       <load-on-startup>1</load-on-startup>
   </servlet>
   <servlet>
       <servlet-name>DBAccessService</servlet-name>


<servlet-class>com.sun.xml.ws.transport.http.servlet.WSServlet</servlet-class> 

       <load-on-startup>1</load-on-startup>
   </servlet>
   <servlet-mapping>
       <servlet-name>DBAccess</servlet-name>
       <url-pattern>/DBAccess</url-pattern>
   </servlet-mapping>
   <servlet-mapping>
       <servlet-name>DBAccessService</servlet-name>
       <url-pattern>/DBAccessService</url-pattern>
   </servlet-mapping>
   <session-config>
       <session-timeout>
           30
       </session-timeout>
   </session-config>
   <welcome-file-list>
       <welcome-file>index.jsp</welcome-file>
   </welcome-file-list>
   <resource-ref>
       <description>
           The database DataSource for the Acme web application.
       </description>
       <res-ref-name>jdbc/MySQL_cellmlrep</res-ref-name>
       <res-type>javax.sql.DataSource</res-type>
       <res-auth>Container</res-auth>
   </resource-ref>
</web-app>


Exception

java.lang.ClassCastException: 
org.apache.tomcat.dbcp.dbcp.BasicDataSource
cannot be cast to javax.naming.Context
       at

org.apache.catalina.core.NamingContextListener.createSubcontexts(NamingContextListener.java:1203) 

       at

org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1015) 

       at

org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:633) 

       at

org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:237) 

       at

org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117) 

       at
org.apache.catalina.core.StandardContext.start(StandardContext.java:4252) 

       at

org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791) 

       at
org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771) 

       at
org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)
       at

org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:627) 

       at

org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:553) 

       at
org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:488)
       at
org.apache.catalina.startup.HostConfig.start(HostConfig.java:1149)
       at
org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311) 

       at

org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117) 

       at
org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
       at
org.apache.catalina.core.StandardHost.start(StandardHost.java:719)
       at
org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
       at
org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
       at
org.apache.catalina.core.StandardService.start(StandardService.java:516) 

       at
org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
       at 
org.apache.catalina.startup.Catalina.start(Catalina.java:578)
       at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
       at

sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 

       at

sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 

       at java.lang.reflect.Method.invoke(Method.java:597)
       at 
org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
       at 
org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)



      


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--
David Smith
Programmer/Analyst
College of Agriculture and Life Sciences
Cornell University
B32 Morrison Hall
Ithaca, NY 14853
Phone: (607) 255-4521


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