Developing Struts Hibernate Plugin
In this section we will develop java code for Struts Hibernate Plugin.
Our Hibernate Plugin will create Hibernate Session factory and cache it in the
servlet context. This strategy enhances the performance of the application.
Source Code Of Hibernate Struts Plugin:
package roseindia.net.plugin;
import java.net.URL;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.action.ActionServlet;
import org.apache.struts.action.PlugIn;
import org.apache.struts.config.ModuleConfig;
import org.hibernate.HibernateException;
public class HibernatePlugIn implements PlugIn {
private String _configFilePath = "/hibernate.cfg.xml";
/**
* the key under which the <code>SessionFactory
</code> instance is stored
* in the <code>ServletContext</code>.
*/
public static final String SESSION_FACTORY_KEY = SessionFactory.class.getName();
private SessionFactory _factory = null;
public void destroy() {
try{
_factory.close();
}catch(HibernateException e){
System.out.println("Unable to close Hibernate Session Factory: " + e.getMessage());
}
}
public void init(ActionServlet servlet,
ModuleConfig config) throws ServletException {
System.out.println("*************************************");
System.out.println("**** Initilizing HibernatePlugIn **********");
Configuration configuration = null;
URL configFileURL = null;
ServletContext context = null;
try{
configFileURL =
HibernatePlugIn.class.getResource(_configFilePath);
context = servlet.getServletContext();
configuration =
(new Configuration()).configure(configFileURL);
_factory = configuration.buildSessionFactory();
//Set the factory into session
context.setAttribute(SESSION_FACTORY_KEY, _factory);
}catch(HibernateException e){
System.out.println("Error while initializing hibernate: " + e.getMessage());
}
System.out.println("**************** *********************");
}
/**
* Setter for property configFilePath.
* @param configFilePath New value of property configFilePath.
*/
public void setConfigFilePath(String configFilePath) {
if ((configFilePath == null) || (configFilePath.trim().length() == 0)) {
throw new IllegalArgumentException("configFilePath cannot be blank or null.");
}
System.out.println("Setting '
configFilePath' to '" + configFilePath + "'...");
_configFilePath = configFilePath;
}
/*(SessionFactory) servletContext.getAttribute
(HibernatePlugIn.SESSION_FACTORY_KEY);
*/
}
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In our plugin class we have define a variable _configFilePath to hold the
name of Hibernate Configuration file.
private String _configFilePath = "/hibernate.cfg.xml";
Following code define the key to store the session factory instance in the
Servlet context.
public static final String SESSION_FACTORY_KEY =
SessionFactory.class.getName();
The init() is called on the startup of the Struts Application. On startup the
session factory is initialized and cached in the Servlet context.
configFileURL = HibernatePlugIn.class.getResource(_configFilePath);
context = servlet.getServletContext();
configuration = (new Configuration()).configure(configFileURL);
_factory = configuration.buildSessionFactory();
//Set the factory into session
context.setAttribute(SESSION_FACTORY_KEY, _factory);
Changes to be done in struts-config.xml file
Configuring Hibernate with Struts is very simple work it requires you to have hibernate.cfg.xml in your WEB-INF/classes directory, and to add the following
line to the struts-config.xml file.
<plug-in className="roseindia.net.plugin.HibernatePlugIn"></plug-in>
Testing the Plugin
Build your application and deploy on the tomcat server. Start tomcat server
and observe the console output. It should display the following line:
log4j:WARN Please initialize the log4j system properly.
*************************************
**** Initilizing HibernatePlugIn **********
*************************************
Aug 7, 2006 10:09:53 AM org.apache.struts.tiles.TilesPlugin initD
|
This means you have successfully configured your Struts Hibernate Plugin with
struts application.
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Current Comments
5 comments so far (post your own) View All Comments Latest 10 Comments:When I download and inplement your code I am getting the following error!!
java.lang.NullPointerException
at roseindia.web.SearchTutorialAction.execute(SearchTutorialAction.java:40)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:763)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:225)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:127)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:230)
at weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42)
at com.grems.struts.BasicFilter.doFilter(BasicFilter.java:52)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:42)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3212)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:121)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:1983)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:1890)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1344)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:181)
Please let me know what I have to do.
Posted by Jennie on Thursday, 06.28.07 @ 23:21pm | #20349
It was nice and useful to novice people
Posted by m.venkatraju on Saturday, 03.17.07 @ 17:58pm | #11998
Hi,
good one to beginners.
regards
raju
Posted by srinivasaraju on Wednesday, 02.7.07 @ 11:33am | #6541
nice and usefull to me.
i want more information regarding hibernate
thanks
mahesh
Posted by mahesh on Thursday, 02.1.07 @ 17:25pm | #5219
hi 2 all.
hello world! It is nice site. Keep working!
best regards
i found you here http://google.com ^^
Posted by marionxlx on Friday, 01.26.07 @ 17:59pm | #4429