hi

i facing a Exception when i want to find the values from my DB using hibernate...
in my Struts Action class i use that code


ProductDAO ob=new ProductDAO();
List list=ob.findByTitle(my search value);
request.setAttribute("products", list);

but it create the Exception can some one Help me out what i m doing wrong and how to prevent or slove that Exception...

Witing fr response

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%%%% Error Creating SessionFactory %%%%
org.hibernate.HibernateException: Hibernate Dialect must be explicitly set
at org.hibernate.dialect.DialectFactory.determineDialect(DialectFactory.java:57)
at org.hibernate.dialect.DialectFactory.buildDialect(DialectFactory.java:39)
at org.hibernate.cfg.SettingsFactory.determineDialect(SettingsFactory.java:378)
at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:110)
at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:1881)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1174)
at com.yourcompany.hibernate.HibernateSessionFactory.<clinit>(HibernateSessionFactory.java:31)
at com.yourcompany.hibernate.BaseHibernateDAO.getSession(BaseHibernateDAO.java:13)
at com.yourcompany.hibernate.ProductDAO.findByProperty(ProductDAO.java:89)
at com.yourcompany.hibernate.ProductDAO.findByTitle(ProductDAO.java:115)
at com.yourcompany.struts.action.ViewAction.execute(ViewAction.java:41)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)
%%%% Error Creating SessionFactory %%%%
org.hibernate.MappingException: Could not read mappings from resource: com/yourcompany/hibernate/Process.hbm.xml
at org.hibernate.cfg.Configuration.addResource(Configuration.java:485)
at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1465)
at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1433)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1414)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1390)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1310)
at com.yourcompany.hibernate.HibernateSessionFactory.rebuildSessionFactory(HibernateSessionFactory.java:69)
at com.yourcompany.hibernate.HibernateSessionFactory.getSession(HibernateSessionFactory.java:53)
at com.yourcompany.hibernate.BaseHibernateDAO.getSession(BaseHibernateDAO.java:13)
at com.yourcompany.hibernate.ProductDAO.findByProperty(ProductDAO.java:89)
at com.yourcompany.hibernate.ProductDAO.findByTitle(ProductDAO.java:115)
at com.yourcompany.struts.action.ViewAction.execute(ViewAction.java:41)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)
Caused by: org.hibernate.DuplicateMappingException: Duplicate class/entity mapping com.yourcompany.hibernate.Process
at org.hibernate.cfg.Mappings.addClass(Mappings.java:118)
at org.hibernate.cfg.HbmBinder.bindRoot(HbmBinder.java:154)
at org.hibernate.cfg.Configuration.add(Configuration.java:386)
at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:427)
at org.hibernate.cfg.Configuration.addResource(Configuration.java:482)
... 29 more
Jun 5, 2008 5:53:53 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet action threw exception
java.lang.NullPointerException
at com.yourcompany.hibernate.ProductDAO.findByProperty(ProductDAO.java:89)
at com.yourcompany.hibernate.ProductDAO.findByTitle(ProductDAO.java:115)
at com.yourcompany.struts.action.ViewAction.execute(ViewAction.java:41)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)

You seem to have three issues here:

1) your dialect is not set, depending on what DB your connecting to you will need someting like this set in your properties file
hibernate.dialect=org.hibernate.dialect.HSQLDialect

2)Caused by: org.hibernate.DuplicateMappingException: Duplicate class/entity mapping com.yourcompany.hibernate.Process

You probably have copy paste issue here, when you have copied a line twice.

3) best practises suggest you abstract away your action layer and db layer by adding a sercive layer

WebLayer -> Service Layer -> DB

I quite often see this when the hibernate.cfg.xml file isn't being read from the file system.

Where have you put that file? Classpath isn't good enough. It must be on the classloader's classpath of the class that creates the Hibernate Configuration object.

Here's a tutorial on setting up Hibernate:

http://jpa.ezhibernate.com/Javacode/learn.jsp?tutorial=01howtogetstartedwithhibernate