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From Brian Cook <bc...@printtime.com>
Subject Re: jndi question
Date Tue, 23 Aug 2005 15:22:44 GMT

Yes you can use JNDI with out using JSTL.  But the only way to configure 
it is to define the JNDI resources in the web.xml and context.xml files. 
    Technically you should be able to use the globally defined JNDI 
resources in server.xml, and I have seen configuration set ups doing it 
when googling.  But could never get them to work.

This highlights another area of seemingly unneeded complication in 
Java/Unix development.  Using JNDI for data sources which was supposed 
to help you save time requires that you redundantly define the JNDI 
resource in at lest 2 if not 3 places.

The admin tool which was also supposed to help save time defines the 
JNDI resources in server.xml which does not really seem to be all that 
helpful.  I am sure there is likely a reason for this but I am ignorant 
of it.  The admin tool is also supposed to let you define JNDI resources 
  per context but it errors out when ever I have tried it.

My experience with the Tomcat Admin and Manager tools is that they are 
worthless.  Of the few steps they try to help with more often that not 
they just return errors when you need to use it.  I removed them both 
and have gone back to doing set ups manually and there has not been much 
of a time difference doing it this way.

Any way for JNDI to work you will have to add the definition for it in 
both web.xml and context.xml in the <<Tomcat 
Folder>>/conf/Catalina/localhost/ folder.  This seems counter productive 
since it makes your app less portable having the data base configuration 
details inside the context and by extent the WAR file but it is what you 
have to do to get it to work right now.

I feel your pain I know it is frustrating spending hours debugging just 
the DB connection but todate that is the reality of Java web app 
development.  It is why I fear we will all be .Net developers some day.


Example :
http://jakarta.apache.org/tomcat/tomcat-5.5-doc/jndi-resources-howto.html

<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();

</CODE>





<WEB.XML>

<resource-ref>
   <description>
     Resource reference to a factory for java.sql.Connection
     instances that may be used for talking to a particular
     database that is configured in the server.xml file.
   </description>
   <res-ref-name>
     jdbc/EmployeeDB
   </res-ref-name>
   <res-type>
     javax.sql.DataSource
   </res-type>
   <res-auth>
     Container
   </res-auth>
</resource-ref>

</WEB.XML>




<CONTEXT FILE>

<Context>

   <Resource 	name="jdbc/EmployeeDB"
		auth="Container"
             	type="javax.sql.DataSource"
		username="dbusername"
		password="dbpassword"
             	driverClassName="org.hsql.jdbcDriver" 	
		url="jdbc:HypersonicSQL:database"
		maxActive="8"
		maxIdle="4"/>

</Context>

</CONTEXT FILE>






Sean Rowe wrote:
> Dirk, I'm sorry I didn't see the difference on the page you sent me to.  
> However, if there is a way I can do this without having to use jstl, I 
> would really like to know.  I was hoping to put the code in a class 
> somewhere that my servlets could use.
> 
> thanks,
> sean
> 
> Dirk Weigenand wrote:
> 
>> Sean,
>>
>>  
>>
>>> --- Urspr√ľngliche Nachricht ---
>>> Von: Sean Rowe <ichabooka@gmail.com>
>>> An: Tomcat Users List <tomcat-user@jakarta.apache.org>
>>> Betreff: Re: jndi question
>>> Datum: Mon, 22 Aug 2005 09:24:10 -0500
>>>
>>> Thanks for responding Dirk.  I've practically memorized the 
>>> documentation on the link you sent:
>>>
>>> // Obtain our environment naming context
>>> Context initCtx = new InitialContext();
>>> Context envCtx = (Context) initCtx.lookup("java:comp/env");
>>>
>>> // Look up our data source
>>> DataSource ds = (DataSource)
>>>  envCtx.lookup("jdbc/EmployeeDB");
>>>
>>> // Allocate and use a connection from the pool
>>> Connection conn = ds.getConnection();
>>> ... use this connection to access the database ...
>>> conn.close();
>>>
>>> Whenever I try this, here's what I get (which led me to trying it the 
>>> way
>>> I posted):
>>>
>>> javax.naming.NameNotFoundException: Name java:comp is not bound in this
>>> Context
>>>
>>>   
>>
>>
>> No. Did you look at
>> http://jakarta.apache.org/tomcat/tomcat-5.5-doc/jndi-datasource-examples-howto.html?

>>
>>
>> I recommend putting the context definition in its own content.xml. On
>> redeploying my application tomcat wouldn't find the driver class anymore.
>>
>> Mind you not the class itself but the definition of what class to load.
>>
>> This problem was solved by putting the context into context.xml.
>>
>> regards
>>       Dirk
>>
>>  
>>
> 
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> 


-- 
Brian Cook
Digital Services Analyst
Print Time Inc.
bcook@printtime.com
913.345.8900


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