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From Brian Cook <bc...@printtime.com>
Subject Re: jndi question
Date Tue, 23 Aug 2005 15:52:17 GMT

Actually the files I listed are NOT in the first post.  It shows the 
server.xml and the code calling it but does not show web.xml or context.xml.

The error you are getting just means that that the JNDI resource being 
called in the code is not defined in both web.xml and context.xml.

In looking at the code snip it in the first post I am not following what 
you are trying to do.  The post is for a JNDI question but in the code 
it looks like you are calling the DB URL directly.  The whole point of 
JDNI being to get specific URL, and configuration info outside of the 
code base.  I am not following what it is you are trying to do here.



Sean Rowe wrote:
> Brian, thank you for replying.  I was afraid my topic was dead.  If you 
> could look at my first post, I listed all the files that you have 
> suggested I take a look at.  I have done everything you have suggested, 
> but am still getting errors.  The error I am getting now is
> 
> javax.naming.NameNotFoundException: Name java:comp is not bound in this 
> Context
> 
> I can't find anything on the net or in any books I've looked at that 
> explains this.  As far as I can tell, java:comp should just be there.  
> Any ideas?  Thanks again.
> 
> Sean
> 
> Brian Cook wrote:
> 
>>
>> 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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