Tomcat7 JDBC pools

Question

I have the following in META-INF

<Context>
   <Resource type="javax.sql.DataSource"
        name="jdbc/TestDB"
        factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
        driverClassName="com.mysql.jdbc.Driver"
        url="jdbc:mysql://localhost:3306/"
        username="mysql_user"
        password="mypassword123"/>
</Context>

In my web.xml I have

<resource-ref>
  <description>DB Connection</description>
  <res-ref-name>jdbc/TestDB</res-ref-name>
  <res-type>javax.sql.DataSource</res-type>
  <res-auth>Container</res-auth>
</resource-ref>

In my Java code I have

Context initContext = new InitialContext();
Context envContext  = (Context)initContext.lookup("java:/comp/env");
DataSource datasource = (DataSource)envContext.lookup("jdbc/TestDB");
con = datasource.getConnection();

When Tomcat is starting up I get the following error and I have mysql-connector-java-5.1.20-bin.jar in my libs folder. Any idea why?

INFO: Starting Servlet Engine: Apache Tomcat/7.0.27
05-Jun-2012 23:16:29 org.apache.naming.NamingContext lookup
WARNING: Unexpected exception resolving reference
java.sql.SQLException: com.mysql.jdbc.Driver
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:242)
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:175)
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:684)
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:616)
at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:479)
at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:135)
at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:114)
at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:101)
at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:501)
at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:224)
at org.apache.naming.factory.ResourceFactory.getObjectInstance(ResourceFactory.java:143)
at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:304)
at org.apache.naming.NamingContext.lookup(NamingContext.java:843)
at org.apache.naming.NamingContext.lookup(NamingContext.java:154)
at org.apache.naming.NamingContext.lookup(NamingContext.java:831)
at org.apache.naming.NamingContext.lookup(NamingContext.java:168)
at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1061)
at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:671)
at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:270)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5161)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1566)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1556)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:247)
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:235)
... 29 more

Answer 1

You're missing the JDBC drivers for MySQL.

Download them from MySQL's website: http://dev.mysql.com/downloads/connector/j/

Add the driver to your classpath, to your project, or to Tomcat's HOME\\lib directory.

Answer 2

I had this issue on Ubuntu with Tomcat7 installed by the apt-get mechanism. The problem was the dbcp used by Tomcat, more specifically commons-dbcp.jar instead of tomcat-dbcp.jar.

To resolve this, I took catalina*.jar and tomcat-dbcp.jar from a copy of Tomcat7 downloaded from the tomcat site and replaced the files in tomcat's lib folder. ( commons-dbcp.jar replaced with tomcat-dbcp.jar ).

See this link .