Thanks for helping.
Sure, here are all my settings.
I use MySQL 5.0.37, Tomcat 5.5.17 and Windows XP SP2 and MySQL Connector/J
5.0.5.
The name of the database that I'd like to connect to is called "akr_db" and the
name of my web-application is called "SZTGKR".
1) I have a context.xml file in my web/Meta-INF directory with the following
contents:
--------- CONTEXT.XML
<?xml version="1.0" encoding="UTF-8"?>
<Context crossContext="true" debug="5" docBase="SZTGKR" path="/SZTGKR"
reloadable="true">
<Logger className="org.apache.catalina.logger.FileLogger"
prefix="localhost_akr_db_log." suffix=".txt" timestamp="true"/>
<Resource auth="Container" name="jdbc/akr_db" type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/akr_db">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
<parameter>
<name>removeAbandoned</name>
<value>true</value>
</parameter>
<parameter>
<name>removeAbandonedTimeout</name>
<value>60</value>
</parameter>
<parameter>
<name>logAbandoned</name>
<value>true</value>
</parameter>
<!-- Maximum number of dB connections in pool. Make sure you
configure your mysqld max_connections large enough to handle
all of your db connections. Set to 0 for no limit.
-->
<parameter>
<name>maxActive</name>
<value>100</value>
</parameter>
<!-- Maximum number of idle dB connections to retain in pool.
Set to 0 for no limit.
-->
<parameter>
<name>maxIdle</name>
<value>30</value>
</parameter>
<!-- Maximum time to wait for a dB connection to become available
in ms, in this example 10 seconds. An Exception is thrown if
this timeout is exceeded. Set to -1 to wait indefinitely.
-->
<parameter>
<name>maxWait</name>
<value>10000</value>
</parameter>
<!-- MySQL dB username and password for dB connections -->
<parameter>
<name>username</name>
<value>balazs</value>
</parameter>
<parameter>
<name>password</name>
<value>12345</value>
</parameter>
<!-- Class name for mm.mysql JDBC driver -->
<parameter>
<name>driverClassName</name>
<value>com.mysql.jdbc.Driver</value>
</parameter>
<!-- The JDBC connection url for connecting to your MySQL dB.
The autoReconnect=true argument to the url makes sure that the
mm.mysql JDBC Driver will automatically reconnect if mysqld closed the
connection. mysqld by default closes idle connections after 8 hours.
-->
<parameter>
<name>url</name>
<value>jdbc:mysql://localhost:3306</value>
</parameter>
</ResourceParams>
</Context>
-----------------------------END OF CONTEXT.XML
I have a java class, that (presumably) creates (or returns...?) my connection
pool:
------------- DBTEST.JAVA
package db_helpers;
import javax.naming.*;
import javax.sql.*;
import java.sql.*;
public class DBTest {
String foo = "Not Connected";
String bar = "Empty";
public void init() {
try{
Context ctx = new InitialContext();
if(ctx == null )
throw new Exception("Boom - No Context");
Context envCtx = (Context) ctx.lookup("java:comp/env");
DataSource ds = (DataSource) envCtx.lookup("jdbc/akr_db");
if (ds != null) {
Connection conn = ds.getConnection();
if(conn != null) {
foo = "Got Connection "+conn.toString();
Statement stmt = conn.createStatement();
ResultSet rst =
stmt.executeQuery(
"select ID_paciens, vezeteknev, keresztnev from
torzs_paciens");
if(rst.next()) {
foo=rst.getString(2);
bar=rst.getString(3);
}
conn.close();
}
}
}catch(Exception e) {
e.printStackTrace();
}
}
public String getFoo() { return foo; }
public String getBar() { return bar;}
}
----------------------------- END OF DBTEST.JAVA
Here, my
Connection conn = ds.getConnection();
statement fails.
And finally I have a JSP, in which I'd like to use my connection pool:
------------------------------ DBTEST.JSP
...
<%
db_helpers.DBTest tst = new db_helpers.DBTest();
tst.init();
%>
<h2>Results</h2>
Foo <%= tst.getFoo() %><br/>
Bar <%= tst.getBar() %>
...
------------------------------ END OF DBTEST.JSP
Do I have anything else to connect to my db using connection pooling?
So again, it's the "Connection conn = ds.getConnection();", where my program
fails, it says
"org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot create JDBC driver of
class '' for connect URL 'null'"
And yes, after the following statement, the url, driverclass and some other
properties of my ds is null:
DataSource ds = (DataSource) envCtx.lookup("jdbc/akr_db");
This might be the problem... why is that?
Thanks for helping again!!
Regards,
BM
----- Original Message ----
From: Christopher Schultz <[EMAIL PROTECTED]>
To: Struts Users Mailing List <user@struts.apache.org>
Sent: Monday, May 21, 2007 2:33:11 PM
Subject: Re: [OT] Connection Pooling
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Balazs,
Balazs Michnay wrote:
> I still cannot estabilish database connection using connection pooling.
> I think I made all the settings I need, but still nothing...
> 1) I have a <context> tag in my server.xml
Can you show us the connection settings you are using? You only showed
the code (which looked fine, except that you don't need to check for
null after you create a new InitialContext... I'm pretty sure that an
object creation can't return null).
- -chris
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