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From David Smith <d...@cornell.edu>
Subject Re: NamingException: Cannot create resource instance
Date Fri, 08 Sep 2006 00:16:01 GMT
The method of defining JNDI resources in tomcat changed from 5.0 to 
5.5.  The book appears to be describing the method for 5.5.  See 
http://tomcat.apache.org/tomcat-5.5-doc/jndi-datasource-examples-howto.html 
for details related to tomcat 5.5.

The java code used in jsps and servlets to access the data source is 
still the same.  That part can come from the book.

--David

Kevin Hart wrote:
> The attachments in my previous message got mangled.  Sorry, I'm a newbie. 
> Here is the relevant portion of the server.xml file (the formatting in this
> will probably get mangled too):
>
> ..
> <DefaultContext>
> <Resource name="jdbc/WroxTC5" auth="Container" type="javax.sql.DataSource"/>
> <ResourceParams name="jdbc/WroxTC5">
> <parameter><name>driverClassName</name><value>com.mysql.jdbc.Driver</value></parameter>
>  <parameter><name>url</name><value>jdbc:mysql://localhost/wroxtomcat</value></parameter>
> <parameter><name>username</name><value>*****</value></parameter>
> <parameter><name>password</name><value>*****</value></parameter>
> <parameter><name>maxActive</name><value>20</value></parameter>
> <parameter><name>maxIdle</name><value>30000</value></parameter>
> <parameter><name>maxWait</name><value>100</value></parameter>
  
> <parameter><name>factory</name><value>org.apache.commons.dbcp.BasicDataSourceFactory</value></parameter>
> </ResourceParams>
> </DefaultContext>
>
>       </Host>
>     </Engine>
>   </Service>
> </Server>
>
> And here is the relevant portion of the web.xml file:
>
> ..
> <resource-ref>
>    <res-ref-name>jdbc/WroxTC5</res-ref-name>
>    <res-type>javax.sql.DataSource</res-type>
>    <res-auth>Container</res-auth>
> </resource-ref>
> </web-app>
>
> The code in the jsp that generates the exception is line 14 of the following
> snippet:
>
> ..
> 11: <%
> 12: InitialContext initCtx = new InitialContext();
> 13: if( initCtx != null ) {
> 14:    DataSource ds = (DataSource)
> initCtx.lookup("java:comp/env/jdbc/WroxTC5");
> 15:    Connection conn = ds.getConnection();
> 16:    Statement stmt = conn.createStatement();
> 17:    ResultSet rset = stmt.executeQuery("select * from employee;");
> ..
>
> As you can see, I'm just trying to get an example working.
>
> Thanks again for any help,
> Kevin
>
> Quoting Kevin Hart <kevin.hart@stanford.edu>:
>
>   
>> Hello,
>>
>> I'm trying to get a jsp to access a mysql database.  I'm using the
>> "preferred" JNDI resources approach with Tomcat, but I keep getting the
>> NamingException: Cannot create resource instance error.  I know others
>> have posted with this error.  I've read some of those posts, but
>> the solutions don't seem to fix the problem in my case.
>>
>> I'm using FC5, MySql 5.0.22 and Apache Tomcat 5.5.15.  I attach the
>> following files:
>>
>> exception.report is a copy of the html page showing the error.
>>
>> common.lib.contents is the output of a script session to show the
>> contents of my /usr/share/tomcat5/common/lib directory.  I have at least
>> the
>> following in there: mysql-connector-java-5.0.3-bin.jar, commons-pool.jar,
>> common-collections.jar, naming-factory.jar and naming-resources.jar.
>>
>> server.xml is my /usr/share/tomcat5/conf/server.xml file.  I have a
>> <Resource> tag inside a <DefaultContext> tag inside the <host>
element
>> (see the end of the file).
>>
>> web.xml is from the jsp-examples/WEB-INF directory.  (I'm just tacking
>> my jdbctest.jsp onto the existing jsp-examples webapp.)  The
>> <resource-ref> tag is at the end of that file.
>>
>> Having no experience with Tomcat, I'm basically following instructions
>> from Wrox's book "Professional Apache Tomcat 5."  I must be misreading
>> it.
>>
>> Thanks in advance,
>> Kevin
>>
>>
>>     
>
>
>
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>   


-- 
David Smith
Network Operations Supervisor
Department of Entomology
Cornell University
2132 Comstock Hall
Ithaca, NY 14853
Phone: (607) 255-9571
Fax: (607) 255-0940


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