DBCP Configuration with Tomcat 4.1.27 and mySQL
From: Tom Martin (webmaster_at_sanjamar.com)
Date: 12/29/03
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Date: 29 Dec 2003 12:24:17 -0800
I'm a Java Web developer NEWBIE that has inherited a website that
fails every 2 hours due to poor connection pooling between Tomcat
4.0.6 and mySQL. In efforts to resolve this problem, I've created
another replica DEVELOPMENT website and upgraded it to Tomcat 4.1.27.
I was told this version of Tomcat supports Database Connection Pooling
(DBCP) better than previous versions.
I followed the instructions as listed at:
<http://jakarta.apache.org/tomcat/tomcat-4.1-doc/jndi-datasource-examples-howto.html>
with minor configurations to adjust for my environment.
Something I've done doesn't seem to be working... Could someone
please assist?
Inserted below, the error message and snippets of the configuration
files; ERROR on WEB PAGE, Server.xml, web.xml, Prop.java, CatMan.java,
and showproducts.jsp.
==========ERROR on WEB PAGE==================
type Exception report
message
description The server encountered an internal error () that prevented
it from fulfilling this request.
exception
org.apache.jasper.JasperException
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)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain...............
root cause
java.lang.NullPointerException
at jsp.sanjamar.test.CatMan.SelectSubCategories(CatMan.java:110)
at jsp.sanjamar.test.CatMan.ListSubCategories(CatMan.java:54)
at org.apache.jsp.showproducts_jsp._jspService(showproducts_jsp.java:135)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:137)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:210)................
==========SERVER.XML=========================
<Host name="www.sanjamar2003.kattare.com" debug="0"
appBase="public_html" unpackWARs="true" autoDeploy="true">
<Alias>sanjamar2003.kattare.com</Alias>
<Alias>maya.kattare.com</Alias>
<Logger className="org.apache.catalina.logger.FileLogger"
directory="logs"
prefix="sanjamar2003.kattare.com_log." suffix=".txt"
timestamp="true"/>
<Context path="/sanjamar" docBase="sanjamar"
debug="5" reloadable="true" crossContext="true">
<Logger className="org.apache.catalina.logger.FileLogger"
prefix="localhost_DBCP_log." suffix=".txt"
timestamp="true"/>
<Resource name="jdbc/sanjamar"
auth="Container"
type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/sanjamar">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
<parameter>
<name>maxActive</name>
<value>100</value>
</parameter>
<parameter>
<name>maxIdle</name>
<value>30</value>
</parameter>
<parameter>
<name>maxWait</name>
<value>10000</value>
</parameter>
<parameter>
<name>removeAbandoned</name>
<value>true</value>
</parameter>
<parameter>
<name>removeAbandonedTimeout</name>
<value>60</value>
</parameter>
<parameter>
<name>username</name>
<value>xxxxxxxxxxxxxxx</value>
</parameter>
<parameter>
<name>password</name>
<value>xxxxxxxxxxxxxxxxx</value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>org.gjt.mm.mysql.Driver</value>
</parameter>
<parameter>
<name>url</name>
<value>jdbc:mysql://dc1-mysql-01.kattare.com:3306/sanjamar</value>
</parameter>
</ResourceParams>
</Context>
</Host>
==========WEB.XML============================
<web-app>
<description>MySQL App</description>
<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/sanjamar</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>
==========Prop.java============================
public Prop() {
// Setting up database connection, etc.
errout = new PrintWriter(System.err);
try {
Class.forName("org.gjt.mm.mysql.Driver");
} catch (ClassNotFoundException e) {
errout.println("ClassNotFoundException: "
+e.getMessage());
System.err.println("ClassNotFoundException: "
+e.getMessage());
} catch (Exception e2) {
System.err.println("Exception: "+e2.getMessage());
}
try {
Context ctx = new InitialContext();
if(ctx == null )
throw new Exception("No Context");
DataSource ds =
(DataSource)ctx.lookup("java:comp/env/jdbc/sanjamar");
if (ds != null) {
Connection con = ds.getConnection();
/*Original Code
con =
DriverManager.getConnection("jdbc:mysql://127.0.0.1/sanjamar",
"xxxxxxxxxxxx", "xxxxxxxxxxx"); */
stmt = con.createStatement();
}
} catch (SQLException ex) {
errout.println("SQLException: "+ex.getMessage());
errout.flush();
System.err.println("SQLException: "+ex.getMessage());
} catch (Exception e2) {
System.err.println("Exception: "+e2.getMessage());
}
} // end constructor
==========CatMan.java==========================
public class CatMan extends Prop { // category manager
public String ListSubCategories(String category) {
// returns the specified subcategories for the provided category
try {
//Get recordset
SelectSubCategories(category);
String errormsgs = new String ("Error no
subcategories");
if (rs==null) return errormsgs;
String subcategory = "";
while (rs.next()) {
String newsubcategory = rs.getString("name");
subcategory = subcategory + "<br><a href='#" + newsubcategory +
"'>" + newsubcategory +"</a>";
}
return subcategory;
} catch (SQLException ex) {
errout.println("Can't get "+category+" subcategory: "+
ex.getMessage());
errout.flush();
System.err.println("Can't get "+category+" subcategory: "+
ex.getMessage());
return null;
}
}
public boolean SelectSubCategories(String MajorCat) {
try {
rs = stmt.executeQuery("SELECT name FROM prodtypes "+
"WHERE category = '"+MajorCat+"' group by name order by name;");
}
catch (SQLException ex) {
errout.println("Can't List Sub Categories: "+ex.getMessage());
errout.flush();
System.err.println("Can't List Sub Categories: "+ex.getMessage());
return false;
}
return true;
}
}
==========showproducts.jsp==========================
<%@ page import="java.net.*" %>
<%@ page import="jsp.sanjamar.test.*" %>
<%
int prodid = 0; // for mouseovers
CatMan cm = new CatMan();
cm.setRequest(request);
PriceDB pdb = new PriceDB();
pdb.setRequest(request);
if (!cm.ListTypes(category)) {
%><h2>Unable to list types for category
<%= category %></h2>
<%
out.flush();
return;
}
while (cm.NextType()) {
prodid++;
String type = cm.GetNext("name");
String subtitle = cm.GetNext("subtitle",false);
int numprods = 0;
pdb.ListProducts(subtitle);
while (pdb.NextProduct()) {
%><a name="<%= pdb.ListCol("prodnum",false) %>">
<%
numprods++;
}
%>
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