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  1. 07-03-2010, 01:47 PM #1
    vovs
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    Default Servlet getting record from MySQL through hibernate. Exception

    Hi

    I am newbie in Java, and it is my first project.
    I have developed a servlet. This servlet is receiving and inserting record into MySQL through hibernate using eclispe ide.
    I have developed the following code:
    Servlet UserManagerServlet
    Java Code: 
    package org.test;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.hibernate.Transaction;

import utils.HibUtil;

public class UserManagerServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    public UserManagerServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		try{
			PrintWriter out = response.getWriter();
			out.println("<html><head><title>Users Manager</title></head><body>");
			
			//Events
			
			if ("store".equals(request.getParameter("action"))) {
				String userName = request.getParameter("userName");
				String userSurname = request.getParameter("userSurname");
				if ("".equals(userName) || "".equals(userSurname)) {
					out.println("<b><i>Please enter user name and user surname.</i></b>");
				} else {
						createAndStoreUser(userName, userSurname);
						out.println("<b><i>Added user</i></b>");
				}
			}
			
			//Create page
			printUserForm(out);
			listUsers(out);
			
			//Footer of the page
			out.println("</body></html>");
			out.flush();

			
		} catch (Exception ex) {
			//if (ServletException.class.isInstance(ex)) {
			if (ex instanceof ServletException){
				throw (ServletException) ex;
			} else {
				throw new ServletException(ex);
			}
		}
	}
	
	private void createAndStoreUser(String userName, String userSurname) {
		
		users user = new users();
		user.setName(userName);
		user.setSurname(userSurname);
		HibUtil.getSessionFactory().getCurrentSession().save(user);
	}

	private void listUsers(PrintWriter out) {
				
		//Transaction tx = HibUtil.getSessionFactory().getCurrentSession().beginTransaction();
		
		List result = HibUtil.getSessionFactory().getCurrentSession().createCriteria(users.class).list();;
		
		for (Iterator iter = result.iterator(); iter.hasNext();){
			users us = (users) iter.next();
			out.println(us.getName()+us.getSurname());
		}
		//tx.commit();
		
	}

	private void printUserForm(PrintWriter out){
		out.println("<h2>Add new user:</h2>");
		out.println("<form>");
		out.println("name: <input name='userName' length='50'/><br/>");
		out.println("surname: <input name='userSurname' length='50'/><br/>");
		out.println("<input type='submit' name='action' value='store'/>");
		out.println("</form>");
	}

}
    class HibUtil
    Java Code: 
    package utils;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.test.users;

public class HibUtil {

	private static final SessionFactory sessionFactory;
    static {
         try {
              sessionFactory = new AnnotationConfiguration().addAnnotatedClass(users.class).configure("hibernate.cfg.xml").buildSessionFactory();
         }catch (Exception e) {
              System.err.println("Initial SessionFactory creation failed." + e);
         throw new ExceptionInInitializerError(e);
         }
    }
    
    public static SessionFactory getSessionFactory() {
         return sessionFactory;
    } 
     
    public static void closeSession(){
         sessionFactory.close();
    }

}
    When I run my code then I find the following exception.

    Java Code: 
    javax.servlet.ServletException: Servlet execution threw an exception


root cause 

java.lang.NoClassDefFoundError: Could not initialize class utils.HibUtil
	org.test.UserManagerServlet.listUsers(UserManagerServlet.java:87)
	org.test.UserManagerServlet.doGet(UserManagerServlet.java:56)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    UserManagerServlet.java:56
    Java Code: 
    listUsers(out);
    UserManagerServlet.java:87
    List result =
    Java Code: 
    HibUtil.getSessionFactory().getCurrentSession().createCriteria(users.class).list();

    Pleas tell me that where I have done the mistake and how can I resolove the error.
    I am sorry for my English:(

    Note:
    For test i have wrote new class DelMe2 and object arn was succesfull added to MySQL

    Java Code: 
    package org.test;

import org.hibernate.Session;
import org.hibernate.Transaction;

import utils.HibUtil;
public class DelMe2 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Session session = HibUtil.getSessionFactory().getCurrentSession();
		Transaction tx = null;
		
		users arn = new users();
		arn.setName("test");
		arn.setSurname("tester");
		try{
			tx = session.beginTransaction();
			session.save(arn);
			tx.commit();
		} catch (Exception ex) {
			if (tx != null){
				tx.rollback();
			}
			System.out.println(ex);
		}finally{
			HibUtil.closeSession();	
		}

		}
}
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  2. 07-03-2010, 02:26 PM #2
    Norm's Avatar
    Norm
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    Default

    You've done an excellent job of posting your question. The best I've seen!!!

    Sorry I don't know your environment. What I see is that your class file is not being found.
    NoClassDefFoundError: Could not initialize class utils.HibUtil
    Check that the HibUtil class file is in the correct location. It needs to be in the utils folder.
    That could be in a jar file.
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  3. 07-03-2010, 03:17 PM #3
    vovs
    vovs is offline Member
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    Default

    Norm, thank you for response. I am happy:D

    I work in Eclipse Helios.
    Check that the HibUtil class file is in the correct location. It needs to be in the utils folder.
    That could be in a jar file.
    But test class DelMe2.class worked..It use same class HibUtil
    :confused:
    My project after deploying


    C:\apache-tomcat-6.0.26\webapps\servlet_db\
    |
    ---META-INF
    |...............|
    |................-----MANIFEST.MF
    ---WEB-INF
    |...............|
    |................-----classes
    |...............|...............|
    |...............|................-org
    |...............|...............|.....|
    |...............|...............|......-test
    |...............|...............|...........|
    |...............|...............|...........-UserManagerServlet.class, DelMe2.class, users.class
    |...............|...............|
    |...............|................-utils
    |...............|.....................|
    |...............|......................-HibUtil.class
    |...............|
    |............... ---- lib(*.jars)
    |...............|
    |............... --web.xml
    |
    -index.jsp
    ffuh..
    Last edited by vovs; 07-03-2010 at 03:24 PM.
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  4. 07-04-2010, 12:32 AM #4
    vovs
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    Default

    I have solved my problem.
    Thanks for everyone...
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