Regards.
Julian Rivera.
Arora, Avinash wrote:
Well I figured out the problem. The problem was that mysql-connector.jar
was not in common/lib of tomcat, but it I had placed in the WEB-INF/lib
of my application. Thanks for every body's suggestion. Also just asking curiosity if we keep same jar in both WEB-INF/lib and
common/lib, will it create some problem.
Thanks.
Avinash Arora
-----Original Message-----
From: Daxin Zuo [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 05, 2004 4:45 PM
To: Tomcat Users List
Subject: RE: DB connection pool problem
Have you tried to put the configuration text in <GlobalNamingResources> instead of <context> block? To me, the message tells that the web.xml and java code is fine. The server.xml is not edited correctly. in you server.xml, you put <ResourceParams name="jdbc/conversion">, but where is the resource "jdbc/conversion"?
-----Original Message----- From: Arora, Avinash [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 05, 2004 4:07 PM To: Daxin Zuo; Tomcat Users List Subject: RE: DB connection pool problem
Hi, Sorry I was messing up my code by making several changes. If I add that statement, I get the following SQL exception is generated Cannot create JDBC driver of class '' for connect URL 'null'. Any idea about what corrections I need to make.
Avinash Arora
-----Original Message----- From: Daxin Zuo [mailto:[EMAIL PROTECTED] Sent: Tuesday, May 04, 2004 4:29 PM To: Tomcat Users List Subject: RE: DB connection pool problem
You have to add con = dataSource.getConnection(); after dataSource = (DataSource)ctx.lookup("jdbc/conversion");
-----Original Message----- From: Arora, Avinash [mailto:[EMAIL PROTECTED] Sent: Tuesday, May 04, 2004 3:54 PM To: David Smith; Tomcat Users List Subject: RE: DB connection pool problem
Sorry for creating the confusion. Actually I was seeing the connection object to be null for long time. But at last moment I made those silly changes to present it in a better way. Sorry about it. But now I printing the connection object and finding it to be null. I cannot understand, the reason for connection object to be null, even when datasource object is not null. Is it because that I am not able to connect to database? If yes what could be the reason. If I specify the attributes, using Direct JDBC by using Class.forName() and DriverManager.getConnection(), I can connect to data base and read all the values. But the problem comes when I use Connection pooling. Where shuld I look for correction??
------------------------------------------------------------------ Part of my code and JSP o/p ----------------------------------------------------------------- public LinkedList selectCP(){ LinkedList ll = new LinkedList(); Connection con = null; Statement stmt = null; ResultSet rs = null; DataSource dataSource = null; try{ Context init = new InitialContext(); Context ctx = (Context) init.lookup("java:comp/env"); dataSource = (DataSource)ctx.lookup("jdbc/conversion"); ll.add("dataSource object is"); ll.add(dataSource); }
catch(NamingException e){ System.out.println("Exception thrown is"+e.getMessage()); ll.add("Naming Exception thrown"); } finally{ if(dataSource == null){ ll.add("DataSource object is null"); return ll; } else{ ll.add("Data source object is not null");
} } try{ ll.add("Inside try."); ll.add("con is"); ll.add(con);
if(con == null){ ll.add("Inside try. Connection object found to be null"); ll.add(con); return ll; } else{ ll.add("Connection object inside else is"); ll.add(con); } } } catch(SQLException e) { System.err.println("SQL EXCEPTION"+e.getMessage()); ll.add("SQL Exception "); ll.add(e.getMessage()); } catch(Exception e) { System.err.println(" class not found exception"+e.getMessage()); ll.add("Exception generated:"); ll.add(e.getMessage()); } finally{ if(con == null) ll.add("Connection object is null"); } try{ stmt.close(); } catch(Exception e){} try{ rs.close(); } catch(Exception e){} try{ con.close(); } catch(Exception e){}
return ll; } ---------------------------O/P------------------------------------------ --- I am pasting the ll obtained on browser-- [dataSource object is, [EMAIL PROTECTED], Data source object is not null, Inside try., con is, null, Inside try. Connection object found to be null, null, Connection object is null]
-----Original Message----- From: David Smith [mailto:[EMAIL PROTECTED] Sent: Tuesday, May 04, 2004 1:35 PM To: Tomcat Users List Subject: Re: DB connection pool problem
Sorry about the last post. It's been a looonnng day and I didn't read it very well :-(.
From what I see, you're comparing conn to null before even attempting to get a connection. Try comparing dataSource to null instead of conn in the second catch block. Then do dataSource.getConnection() if dataSource != null.
--David
David Smith wrote:
I'm a bit confused on your code:nul");
try{ // load the driver class file //Class.forName("com.mysql.jdbc.Driver").newInstance(); //establishing the connection if(con == null){ ll.add("Inside 1st try. Connection object found to be null");
Why are you doing a Class.forName call after getting a datasource object? I think you're mixing incompatible database access methods. Try doing dataSource.getConnection() after getting a valid datasource instead. You'll be happier with the result. Take a look at the javadocs for javax.sql.DataSource for more info.
--David
Arora, Avinash wrote:
Hi friends, Thanks for your previous feedback. After adding several logging statements in my code, I have found that connection object is null. But dataSource object is not null. What can be reason for it?? Here is how I use it in my code-- public LinkedList testFunction(){ LinkedList ll = null; Connection con = null; Statement stmt = null; ResultSet rs = null; DataSource dataSource = null; try{ Context init = new InitialContext(); Context ctx = (Context) init.lookup("java:comp/env"); dataSource = (DataSource)ctx.lookup("jdbc/conversion"); ll.add("dataSource object is"); ll.add(dataSource); } catch(NamingException e){ System.out.println("Exception thrown is"+e.getMessage()); ll.add("Naming Exception thrown"); } finally{ if(dataSource == null){
ll.add("DataSource object is null");
return ll;
}
else{
ll.add("Data source object is not null");
// return ll;
}
}
try{
// load the driver class file
//Class.forName("com.mysql.jdbc.Driver").newInstance();
//establishing the connection
if(con == null){
ll.add("Inside 1st try. Connection object found to be
null");
}
else{
ll.add("Inside 1st try. Connection object is not
page,con = dataSource.getConnection();
stmt = con.createStatement();
....
}
finally{
if(con == null){
ll.add("Connection object is null");
// return ll;
}
----------------------Here is the output that I can see on my jsp
above.where I try to print out the linklist obtained from the function
Connectionelements of link list read from database are -[dataSource object is,
[EMAIL PROTECTED], Data source object is
not null, Inside 1st try. Connection object found to be null,
theyobject is null]
Thanks. Avinash Arora
-----Original Message----- From: Daxin Zuo [mailto:[EMAIL PROTECTED] Sent: Monday, May 03, 2004 3:34 PM To: Tomcat Users List Subject: RE: DB connection pool problem
I have just created a "pool" -- I hope it is really a pool. I used jtds jdbc driver to MS SQL Server on Windows. You may find some thing similar. Holp it helps.
1) bellow is the text in tomcat\conf\server.xml <GlobalNamingResources> <Resource name="jdbc/DirectSQL" auth="Container" type="javax.sql.DataSource"/> <ResourceParams name="jdbc/DirectSQL"> <parameter> <name>factory</name> <value>org.apache.commons.dbcp.BasicDataSourceFactory</value> </parameter>
<parameter> <name>maxActive</name> <value>255</value> </parameter> <parameter> <name>maxIdle</name> <value>10</value> </parameter> <parameter> <name>maxWait</name> <value>10000</value> </parameter> <parameter> <name>username</name> <value>user1</value> </parameter> <parameter> <name>password</name> <value>passwd1</value> </parameter> <parameter> <name>driverClassName</name> <value>net.sourceforge.jtds.jdbc.Driver</value> </parameter> <parameter> <name>url</name> <value>jdbc:jtds:sqlserver://serverName:1433</value> </parameter> </ResourceParams> ...
2) bellow is the text in tomcat\conf\Catalina\localhost\ROOT.XML --I create this file by myself <Context path="" docBase="ROOT" debug="0" privileged="true">
<!-- Link to the user database using dbc:jtds:sqlserver -->
<ResourceLink name="jdbc/DirectSQL" global="jdbc/DirectSQL"
type="javax.sql.DataSource"/>
</Context>
This "name" is used in Java code. "global" is the name in xml file.
created acan be different.
3) my test jsp file is in \tomcat\webapps\ROOT\zuo\
Context ctx = new InitialContext(); if (ctx == null) { throw new Exception("Boom - No Context"); } DataSource ds = (DataSource) ctx.lookup("java:comp/env/jdbc/DirectSQL"); if (ds != null) con = ds.getConnection(); if (con != null){ str = "select * from myTable"; pStateSearch = con.prepareStatement(str, ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY ); rs = pStateSearch.executeQuery(); ....
That's all.
-----Original Message----- From: Arora, Avinash [mailto:[EMAIL PROTECTED] Sent: Monday, May 03, 2004 3:10 PM To: Tomcat Users List Subject: DB connection pool problem
Hi,
I am also having the problem with the connection pools. Since I am
writing an application first time by using connection pools, I
andtest application DBTest. I edited my server.xml and web.xml (of my application in following way-- #added to server.xml <Context path="/DBTest" docBase="DBTest" debug="0" reloadable="true"> <ResourceParams name="jdbc/conversion"> <parameter> <name>username</name> <value>ROOT</value> </parameter> <parameter> <name>password</name> <value>PASSWORD</value> </parameter> <parameter> <name>driverClassName</name> <value>com.mysql.jdbc.Driver</value> </parameter> <parameter> <name>url</name> <value>jdbc:mysql://localhost/DB</value> </parameter> </ResourceParams> </Context>
#web.xml
<web-app>
<description>MySQL Test App</description>
<resource-ref>
<res-ref-name>jdbc/conversion</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>
And I added the following statements to my Java class, (which works
fine, when I use the connection objects by hardcoding the username
trieddb).--
Context init = new InitialContext(); Context ctx = (Context) init.lookup("java:comp/env"); DataSource dataSource = (DataSource)ctx.lookup("jdbc/conversion");
But even after, making these changes, I cannot read any thing from
database. I was wondering what more changes I need to made. I also
anto run my JAVA class (DAO) from command line, but I get the following exception--
Need to specify class name in environment or system property, or as
problem?applet parameter, or in an application resource file: java.naming.factory.initial
I tried to print outs the place where exception occurs in my code and found that exception occurs at dataSource = (DataSource)ctx.lookup("jdbc/conversion");
Can any body please comment on whats going on wrong? When I run from
command line, is tomcat used, I don't think so? So where is the
Any ideas?? Avinash Arora
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