SQLNestedException

[kwame Iwegbue]

Can someone help with this Exception.

I am using Tomcat 5.5 ..
here is the complete stack trace

  
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot create JDBC driver of class '' for connect URL 'null'
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:780)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:540)
at hopenet.utils.ConnectionUtil.getConnection(ConnectionUtil.java:26)
at hopenet.utils.Patient_DB.getPatientInfo(Patient_DB.java:83)
at hopenet.PatientSearchServlet.doGet(PatientSearchServlet.java:76)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:667)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:595)
Caused by: java.sql.SQLException: No suitable driver
at java.sql.DriverManager.getDriver(DriverManager.java:243)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:773)
... 20 more

This is CATALINA_HOME/conf/context.xml

    
<!-- The contents of this file will be loaded for each web application -->
<Context>
 
    <!-- Default set of monitored resources -->
    <WatchedResource>WEB-INF/web.xml</WatchedResource>

    <!-- Uncomment this to disable session persistence across Tomcat restarts -->
    <!--
    <Manager pathname="" />
    -->

 <Resource name="jdbc/DB" 
 auth="Container"
            type="javax.sql.DataSource" 
            username="admin" 
            password="pass"
            driverClassName="com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource" 
            url="jdbc:mysql://localhost/hopenet"
            maxActive="20" 
            maxIdle="4"
            timeBetweenEvictionRunsMillis="6000" />
</Context>

[ June 10, 2006: Message edited by: kwame Iwegbue ]

[John G Martinson]

With out your code, which can be extensive, it looks like somewhere you are trying to load a class named "for connect URL 'null'"

One thing i would like to see is what your hopenet.utils.ConnectionUtil.getConnection() looks like. This appears to be where the problem actually is

[kwame Iwegbue]

seems to work when <Resource> is placed in CATALINA_HOME/conf/server.xml under <GlobalNamingResources> and then place <ResourceLink> in the context.xml file.

[kwame Iwegbue]

I have finally figured this out!!!

(This should probably be in Tomcat section, instead of here in JDBC)

From what I've seen in several other forums online regarding this problem, there might be either a bug in Tomcat v5.5, or the issue is not yet properly documented.

When trying to configure a web applications to access JDBC by using a DataSource to return a java.sql.Conncetion from Connection pool, you might encounter an
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot create JDBC driver of class '' for connect URL 'null'

This occurs when trying to run this type of code:

  
 
Context initCtx = new InitialContext();
Context envCtx = (Context) initCtx.lookup("java:comp/env");
DataSource ds = (DataSource)
  envCtx.lookup("jdbc/EmployeeDB");
 
Connection conn = ds.getConnection();
 
... use this connection to access the database ...
 
conn.close();

I believe it could be because there was a problem creating the Context. This could be fixed by using 'attributes' in <Resource> tag of <Context> element, instead of <Parameter> as in prev Tomcat versions, then by placing <Resource> in CATALINA_HOME/conf/server.xml under <GlobalNamingResources> and then place a <ResourceLink> in the context.xml file.

Problem is, when trying to perform

 
Context envCtx = (Context) initCtx.lookup("java:comp/env");   

you might still get a
javax.naming.NameNotFoundException: Name jdbc is not bound in this Context

So next you need to place a factory attribute in <Resource>. There is a default factory provided by Tomcat v5.5, but this doesn't seen to work for Connection pooling. So you can use

factory="org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory"

This works whether <Resource> is defined under <GlobalNamingResources> in server.xml for global access, and then <ResourceLink> is defined under <Context> for each application, or if <Resource> is placed under <Context> only. An example (saved as /META-INF/context.xml):

 
<?xml version="1.0" encoding="UTF-8"?>
<Context path="/webApp" docBase="webApp" reloadable="true" overide="true" crossContext="true">
 <Resource name="jdbc/EmployeeDB" 
 auth="Container"
            type="javax.sql.DataSource" 
            factory="org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory"
            username="myusername" 
            password="mypassword"
         driverClassName="com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource" 
            url="jdbc:mysql://localhost/mydatabase"
            maxActive="20" 
            maxIdle="10"
            maxWait="-1"
            removeAbandonded="true"
            removeAbandondedTimeout="60"
            timeBetweenEvictionRunsMillis="60000" /> 
</Context>  

I hope this is helpful to someone!
[ June 15, 2006: Message edited by: kwame Iwegbue ]