How to create Connection pool in Tomcat 5

Question

present i am developing one web site in that i am using tomcat 5.
i am trying to establish connection pooling in tomcat,i am facing some problems..
tomcat throws the following exception ie.,
cannot create JDBC Driver class for connect URL null.
my code lik this
i configured the web.xml
<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app>
<resource-ref>
<description>Oracle Datasource example</description>
<res-ref-name>sqlserver</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>
my server.xml
<?xml version='1.0' encoding='utf-8'?>
<Server>
<Listener className="org.apache.catalina.mbeans.ServerLifecycleListener"/>
<Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener"/>
<GlobalNamingResources>
<Environment name="simpleValue" type="java.lang.Integer" value="30"/>
<Resource auth="Container" description="User database that can be updated and saved" name="UserDatabase" type="org.apache.catalina.UserDatabase"/>
<Resource auth="Container" name="sqlserver" type="javax.sql.DataSource"/>
<ResourceParams name="UserDatabase">
<parameter>
<name>factory</name>
<value>org.apache.catalina.users.MemoryUserDatabaseFactory</value>
</parameter>
<parameter>
<name>password</name>
<value>sudha</value>
</parameter>
<parameter>
<name>pathname</name>
<value>conf/tomcat-users.xml</value>
</parameter>
<parameter>
<name>username</name>
<value>sudha</value>
</parameter>
</ResourceParams>
<ResourceParams name="sqlserver">
<parameter>
<name>url</name>
<value>jdbc:odbc:SQL</value>
</parameter>
<parameter>
<name>validationQuery</name>
<value>select * from employee</value>
</parameter>
<parameter>
<name>maxIdle</name>
<value>4</value>
</parameter>
<parameter>
<name>maxActive</name>
<value>8</value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>sun.jdbc.odbc.JdbcOdbcDriver</value>
</parameter>
<parameter>
<name>maxWait</name>
<value>5000</value>
</parameter>
<parameter>
<name>username</name>
<value>kpi</value>
</parameter>
<parameter>
<name>factory</name>
<value>org.apache.naming.factory.DbcpDataSourceFactory</value>
</parameter>
<parameter>
<name>password</name>
<value>kpi</value>
</parameter>
</ResourceParams>
</GlobalNamingResources>
<Service name="Catalina">
<Connector acceptCount="100" connectionTimeout="20000" disableUploadTimeout="true" port="8080" redirectPort="8443" maxSpareThreads="75" maxThreads="150" minSpareThreads="25">
</Connector>
<Connector port="8009" protocol="AJP/1.3" protocolHandlerClassName="org.apache.jk.server.JkCoyoteHandler" redirectPort="8443">
</Connector>
<Engine defaultHost="localhost" name="Catalina">
<Host appBase="webapps" name="localhost">
<Logger className="org.apache.catalina.logger.FileLogger" prefix="localhost_log." suffix=".txt" timestamp="true"/>
</Host>
<Logger className="org.apache.catalina.logger.FileLogger" prefix="catalina_log." suffix=".txt" timestamp="true"/>
<Realm className="org.apache.catalina.realm.UserDatabaseRealm"/>
</Engine>
</Service>
</Server>
and i studied the the tomcat documentation in that tomcat mentioned
The configuration properties for Tomcat's standard data source resource factory (org.apache.naming.factory.DbcpDataSourceFactory) are as follows:
driverClassName - Fully qualified Java class name of the JDBC driver to be used.
maxActive - The maximum number of active instances that can be allocated from this pool at the same time.
maxIdle - The maximum number of connections that can sit idle in this pool at the same time.
maxWait - The maximum number of milliseconds that the pool will wait (when there are no available connections) for a connection to be returned before throwing an exception.
password - Database password to be passed to our JDBC driver.
url - Connection URL to be passed to our JDBC driver. (For backwards compatibility, the property driverName is also recognized.)
user - Database username to be passed to our JDBC driver.
validationQuery - SQL query that can be used by the pool to validate connections before they are returned to the application. If specified, this query MUST be an SQL SELECT statement that returns at least one row.
how to configure server.xml file
and how to get the org.apache.naming.factory.DbcpDataSourceFactory
please help me...this module is very very urgen to me..

Answer 1

I spent many hours when i first implemented connection pooling trying to put it together. The information is scattered and the config has changed slightly from 5.0 to 5.5 etc. This is how I got it working in 5.5.17:
* server.xml seems to be a wrong place for the pool configuration if you consider it to be an application specific thing. It might be a better idea to put it into C:\tomcat55\conf\Catalina\localhost\ConfigFileForYourWeapp.xml as follows:
<Context path="/ClientLink" docBase="C:\eclipseWorkspace\PortfolioUI3\WebRoot">
      <Resource name="jdbc/testportfolios" auth="Container"
                     type="javax.sql.DataSource"
                     factory="org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory"
                     username="****" password="******"
                     driverClassName="com.mysql.jdbc.Driver"
                     url="jdbc:mysql://192.168.0.101:3306/testportfolios?user=***********&password=***********&useUnicode=true&characterSet=swedish"
                     maxWait="10000" maxActive="30" maxIdle="10" removeAbandoned="true"
                     removeAbandonedTimeout="60" logAbandoned="true" testWhileIdle="true"
                     minEvictableIdleTimeMillis="4000"
                     timeBetweenEvictionRunsMillis="60000" validationQuery="SELECT '1'" />
      </Context>* Then add the following snippet into web.xml in your webapp directory:
<resource-ref>
                <description>Database pool defined in ClientLink.xml</description>
                <res-ref-name>jdbc/testportfolios</res-ref-name>
                <res-type>javax.sql.DataSource</res-type>
                <res-auth>Container</res-auth>
           </resource-ref>* Next put the jdbc-driver jar in a place where tomcat can find it. That is common\lib. Note that the shared/lib does not work.
* Get connections in java as follows:
                try {
                     Context initCtx = new InitialContext();
                     DataSource ds = (DataSource) initCtx.lookup("java:comp/env/jdbc/testportfolios");
                     this.connection = ds.getConnection();
                } catch (NamingException e) {
                     throw new RuntimeException("Java naming exception when getting connection from tomcat pool: " + e.getMessage());
                }I hope that this helps you to save the time I lost figuring this out!
Message was edited by:
Tomppu