Tomcat 4.1: Setting Up Connection Pooling, Adding Resource to server.xml
The question relates to my home study of the Tomcat Server via the book
referenced below.
Added Context via Tomcat Administration page.
Added Resource, ResourceParams, and parameter tags by hand-editing
the server.xml file, and re-starting.
Reference: Ian McFarland, Peter Harrison, Mastering Tomcat Development,
Wiley Publishing, Inc., p. 283-284.
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In Tomcat Administration Page:
Clicking on Data Sources, under Resources, under Context /tomcatbook,
under Host, gives the
following exception, perhaps indicating Tomcat 4.1 is not compatible
with this XML setup. Exception truncated for brevity's sake.
exception
org.apache.jasper.JasperException: Exception retrieving attribute
'driverClassName'
at
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:254)
at
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
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Changes to $CATALINA/HOME/server.xml (Context tag added by Tomcat
Administration page,
inside Context tag manually added via text editor, as recommended by
referenced book):
Context className=org.apache.catalina.core.StandardContext
cachingAllowed=true
charsetMapperClass=org.apache.catalina.util.CharsetMapper
cookies=true crossContext=false debug=0 docBase=tomcatbook
mapperClass=org.apache.catalina.core.StandardContextMapper
path=/tomcatbook privileged=false reloadable=true
swallowOutput=false useNaming=false
wrapperClass=org.apache.catalina.core.StandardWrapper
Resource name=jdbc/tomcatbook auth=Container
type=javax.sql.DataSource
ResourceParams name=jdbc/tomcatbook
parameter
nameuser/name
valuetomcatbook/value
/parameter
parameter
namepassword/name
valuePasswordIntentionallyChangedToProtectMeFromTheGuilty/value
/parameter
parameter
namedriverClassName/name
valuecom.mysql.jdbc.Driver/value
/parameter
parameter
nameurl/name
valuejdbc:mysql://localhost.localdomain/tomcatbook/value
/parameter
/ResourceParams
/Resource
/Context
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Should I create a New Data Source in the Tomcat Administration Tool?
Would the following values be correct?
PropertyValue
JNDI Name: jdbc/tomcatbook
Data Source URL:jdbc:mysql://localhost.localdomain/tomcatbook
JDBC Driver Class: com.mysql.jdbc.Driver
User Name: tomcat
Password: PasswordIntentionallyChangedToProtectMeFromTheGuilty
Max. Active Connections:4
Max. Idle Connections: 2
Max. Wait for Connection: 5000
Validation Query: ??? select login, password from user
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Server Information
Tomcat Version Apache Tomcat/4.1.24-LE-jdk14
JVM Version 1.4.2-b28
JVM Vendor Sun Microsystems Inc.
OS Name Linux
OS Version 2.4.20-31.9
OS Architecture i386
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Working Java code:
import java.sql.* ;
public class TestMySQL3
{
public static void main ( String [] args )
throws Exception
{
Class.forName(com.mysql.jdbc.Driver).newInstance();
Connection connection = null ;
Statement statement = null ;
ResultSet resultSet = null ;
String query = select login, password from user ;
try
{
connection = DriverManager.getConnection (
jdbc:mysql://localhost/tomcatbook,
tomcat,
PasswordIntentionallyChangedToProtectMeFromTheGuilty ) ;
statement = connection.createStatement () ;
resultSet = statement.executeQuery ( query ) ;
while ( resultSet.next () )
{
String login=
resultSet.getString ( 1 ) ;
String password =
resultSet.getString ( 2 ) ;
System.out.println ( login: + login +
password: + password ) ;
}
}
finally
{
if ( resultSet != null )
resultSet.close () ;
if ( statement != null )
statement.close () ;
if (
Re: Tomcat 4.1: Setting Up Connection Pooling, Adding Resource to server.xml,
I missed the following important information that was in the Tomcat
documentation, that wasn't in the book I was reading. I am currently
getting the following exception in my log file when executing a servlet
that obtains a DataSource using the JNDI InitialContext. I previously
thought it might be a class not defined exception because I didn't
supply the connection pooling .jar files as required by the
instructions.
2004-11-26 20:15:24 org.apache.catalina.INVOKER.ClientListPooledServlet:
ClientListPooledServlet.init:
javax.naming.NameNotFoundException: Name java:comp is not bound in this
Context
at
org.apache.naming.NamingContext.lookup(NamingContext.java:811)
at
org.apache.naming.NamingContext.lookup(NamingContext.java:194)
at javax.naming.InitialContext.lookup(InitialContext.java:347)
at ClientListPooledServlet.init(ClientListPooledServlet.java:25)
From ClientListPooledServlet.java. Line 25 is the one with the new
InitialContext () constructor call.
public void init ( ServletConfig config )
throws ServletException
{
super.init ( config ) ;
log ( ClientListPooledServlet.init entered ) ;
try
{
// Context initCtx = new InitialContext () ;
// Context envCtx = (Context) initCtx.lookup (
java:comp/env ) ;
// ds = (DataSource) envCtx.lookup (
jdbc/tomcatbook ) ;
ds = (DataSource) new InitialContext ().lookup (
java:comp/env/jdbc/tomcatbook ) ;
}
catch ( Exception e )
{
log ( ClientListPooledServlet.init: +
e.getMessage () ) ;
log ( ClientListPooledServlet.init: , e ) ;
throw new UnavailableException ( e.getMessage ()
) ;
}
log ( ClientListPooledServlet.init exiting ) ;
}
DBCP uses the Jakarta-Commons Database Connection Pool. It relies on
number of Jakarta-Commons componenets:
* Jakarta-Commons DBCP 1.0
* Jakarta-Commons Collections 2.0
* Jakarta-Commons Pool 1.0
These jar files along with your the jar file for your JDBC driver should
be installed in $CATALINA_HOME/common/lib.
I don't know if these versions are close enough, or not.
If not, I can go through the Jakarta Archives looking for
closer versions.
[EMAIL PROTECTED] logs]$ ll -rt $CATALINA_HOME/common/lib
...
-rw-r--r--1 davidstevenson 175426 Nov 26 20:06
commons-collections-2.1.1.jar
-rw-r--r--1 davidstevenson42492 Nov 26 20:06
commons-pool-1.2.jar
-rw-r--r--1 davidstevenson 107631 Nov 26 20:08
commons-dbcp-1.2.1.jar
Based on the Tomcat Documentation, I revamped the server.xml
configuration (I haven't modified this yet to include the
instructions under Preventing dB connection pool leaks in
http://jakarta.apache.org/tomcat/tomcat-4.1-doc/jndi-datasource-examples-howto.html).
Context className=org.apache.catalina.core.StandardContext
cachingAllowed=true
charsetMapperClass=org.apache.catalina.util.CharsetMapper
cookies=true
crossContext=false debug=9 docBase=tomcatbook
mapperClass=org.apache.catalina.core.StandardContextMapper
path=/tomcatbook privileged=false reloadable=true
swallowOutput=false
useNaming=false
wrapperClass=org.apache.catalina.core.StandardWrapper
displayName=Mastering Tomcat Development
Logger className=org.apache.catalina.logger.FileLogger
prefix=localhost_tomcatbook_log. suffix=.txt
timestamp=true/
Resource name=jdbc/tomcatbook auth=Container
type=javax.sql.DataSource
ResourceParams name=jdbc/tomcatbook
parameter
namefactory/name
valueorg.apache.commons.dbcp.BasicDataSourceFactory/value
/parameter
parameter
namemaxActive/name
value100/value
/parameter
parameter
namemaxIdle/name
value30/value
/parameter
parameter
namemaxWait/name
value1/value
/parameter
parameter
nameusername/name
valuetomcat/value
/parameter
parameter
namepassword/name
valueRealPasswordOmitted/value
/parameter
parameter
namedriverClassName/name
valuecom.mysql.jdbc.Driver/value
/parameter
parameter
nameurl/name
valuejdbc:mysql://localhost/tomcatbook?autoReconnect=true/value
/parameter
/ResourceParams
/Resource
/Context
$ more $CATALINA_HOME/webapps/tomcatbook/WEB-INF/web.xml
...
resource-ref
description
This is a reference to the data source we use
to talk to the database configured in the
server.xml file.
/description
res-ref-namejdbc/tomcatbook/res-ref-name
