[karman6311]

Hi, I am experiencing a database connection pool issue, I can use generic method to access MySQL via JDBC, when I switch to Database connection pool code, I got erroe “Cannot load JDBC driver class ‘com.mysql.jdbc.Driver'”, I do not configue path and classpath, I think Myeclipse has done that, how can I solve this problem?

Need help, thx,

yibing

[Loyal Water]

Can you go to MyEclipse > Installation Summary > Installation Details and paste the information here for me.

Can you paste the entire error message here for me.

Can you paste you code here for me as well.

[karman6311]

I list error message when I click “Submit” to store form data.

INFO: Find registry server-registry.xml at classpath resource
Oct 5, 2008 12:41:27 AM org.apache.catalina.startup.Catalina start
INFO: Server startup in 2750 ms
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot load JDBC driver class ‘com.mysql.jdbc.Driver’
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1136)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880)
at data.ConnectionPool.getConnection(ConnectionPool.java:38)
at data.UserDB.emailExists(UserDB.java:99)
at email.AddToEmailListServlet.doGet(AddToEmailListServlet.java:30)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1130)
… 20 more
Oct 5, 2008 12:41:51 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet AddToEmailListServlet threw exception
java.lang.NullPointerException
at data.ConnectionPool.freeConnection(ConnectionPool.java:51)
at data.UserDB.emailExists(UserDB.java:121)
at email.AddToEmailListServlet.doGet(AddToEmailListServlet.java:30)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Thread.java:619)

my web.xml
<?xml version=”1.0″ encoding=”UTF-8″?>
<web-app version=”2.5″ xmlns=”http://java.sun.com/xml/ns/javaee&#8221; xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance&#8221; xsi:schemaLocation=”http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd”&gt;

<resource-ref>
<description>DBCP Connection</description>
<res-ref-name>jdbc/testDB</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>

<servlet>
<servlet-name>AddToEmailListServlet</servlet-name>
<servlet-class>email.AddToEmailListServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AddToEmailListServlet</servlet-name>
<url-pattern>/addToEmailList</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>30</session-timeout>
</session-config>
<welcome-file-list>
<welcome-file>join_email_list.jsp</welcome-file>
</welcome-file-list>
</web-app>

my context.xml

<?xml version=”1.0″ encoding=”UTF-8″?>
<Context path=”/Email”>

<!– maxActive: 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.
–>
<!– maxIdle: Maximum number of idle dB connections to retain in pool.
Set to -1 for no limit. See also the DBCP documentation on this
and the minEvictableIdleTimeMillis configuration parameter.
–>
<!– maxWait: 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.
–>
<!– username and password: MySQL dB username and password for dB connections –>
<!– driverClassName: Class name for the old mm.mysql JDBC driver is
org.gjt.mm.mysql.Driver – we recommend using Connector/J though.
Class name for the official MySQL Connector/J driver is com.mysql.jdbc.Driver.
–>
<!– url: 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.
–>
<!– logAbandoned, removeAbandoned, removeAbandonedTimeout: Control whether
the container will prevent connection pool leaks by automatically removing
Connection, Statement, ResultSet, etc. objects that haven’t been closed
–>

<Resource name=”jdbc/testDB” auth=”Container” type=”javax.sql.DataSource”
maxActive=”100″ maxIdle=”30″ maxWait=”10000″
username=”root” password=”” driverClassName=”com.mysql.jdbc.Driver”
url=”jdbc:mysql://localhost:3306/test?autoReconnect=true”
logAbandoned=”true” removeAbandoned=”true” removeAbandonedTimeout=”60″ />

</Context>

[Loyal Water]

Are you working with MyEclipse Tomcat?

You need to make sure the JDBC driver is in the Tomcat /lib dir before firing it up OR it is deployed with the project.

[Author]

Posts