Problem with DB in struts app

Question

Hi,
I have made a struts app to get data from mysql DB i am getting follwoing erer
java.lang.NoClassDefFoundError: org/apache/commons/pool/impl/GenericObjectPool
at java.lang.Class.getDeclaredConstructors0(Native Method)
at java.lang.Class.privateGetDeclaredConstructors(Class.java:2328)
at java.lang.Class.getConstructor0(Class.java:2640)
at java.lang.Class.newInstance0(Class.java:321)
at java.lang.Class.newInstance(Class.java:303)
at org.apache.struts.util.RequestUtils.applicationInstance(RequestUtils.java:231)
at org.apache.struts.action.ActionServlet.initModuleDataSources(ActionServlet.java:1081)
at org.apache.struts.action.ActionServlet.init(ActionServlet.java:472)
at javax.servlet.GenericServlet.init(GenericServlet.java:212)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:888)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:621)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:163)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:144)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:596)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:433)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:948)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2358)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:133)
pl help

Answer 1

hi,
iam have got the same poblem in tomcat and i got solution.so if ur using tomcat this solution would be helpfull.
1) check weather u have ur jdbc jars (ojdbc-14.jar for oracle) in CATALINA_HOME/common/lib folder.
2) next check weather u have some thing like this in ur file named as <urwebapp>.xml in CATALINA_HOME/conf/Catalina/<servername or localhost> .i thiink this file is called as ur webapp context xml file (further i will refer this with context.xml).
<Context docBase="<location of ur webapp>" path="/<urappname>">
<Resource auth="Container" driverClassName="fully qualified driver classname" maxActive="20" maxIdle="10" maxWait="-1" name="jdbc/<urDBLOKKUPNAME>" password="<urdb password>" type="javax.sql.DataSource" url="<dburl>" username="<ur db username>"/>
<ResourceParams name="jdbc/<urDBLOKKUPNAME>">
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>fill with the above value</value>
</parameter>
<parameter>
<name>url</name>
<value>fill with the above value</value>
</parameter>
<parameter>
<name>username</name>
<value>fill with the above value</value>
</parameter>
<parameter>
<name>password</name>
<value>fill with the above value</value>
</parameter>
<parameter>
<name>maxActive</name>
<value>20</value>
</parameter>
<parameter>
<name>maxIdle</name>
<value>10</value>
</parameter>
<parameter>
<name>maxWait</name>
<value>-1</value>
</parameter>
</ResourceParams>
</Context>
3) type this in ur web.xml
<resource-ref>
<description>fill with the above value</description>
<res-ref-name>fill with the above value</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
<res-sharing-scope>Shareable</res-sharing-scope>
</resource-ref>
4) lookup in ur java code as
private javax.sql.DataSource getDB() throws javax.naming.NamingException {
javax.naming.Context c = new javax.naming.InitialContext();
return (javax.sql.DataSource) c.lookup("java:comp/env/jdbc/<ur lookupname given in web.xml.and context.xml>");
5) callthis method it will return a datasource object and u can get connection from it
Connection con = getDB().getConnection();
hope this will help u.
regards,
varma