2008年3月5日

Fix Hibernate ERROR: hibernate Transaction not successfully started

I am a freshman of hibernate. Today I configured the tutorial hibernate application following the hibernate reference(3.2). By the way, the refenrence is rather excellent. Everything went well until I came to the first Servlet Page. Error printed as followed:

hibernate Transaction not successfully started

I then checked the codes and configurations. The former program ran well on console, but when it came to Servlet it failed. Refering to some articles found, I refactoried the code. The diffrence is that I stated a Transaction variable tx. It then works. The file EventManagerServlet.java is as below:

package com.CarlElit.HelloWorld.events;

import java.util.Date;
import com.CarlElit.HelloWorld.util.HibernateUtil;
import org.hibernate.Session;
import org.hibernate.Transaction;
import java.util.List;
import java.text.SimpleDateFormat;
import java.util.Iterator;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.ServletException;
import java.io.IOException;
import java.io.PrintWriter;

public class EventManagerServlet extends HttpServlet {
    static final private String CONTENT_TYPE = "text/html,charset=utf-8";
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
        SimpleDateFormat dateFormatter = new SimpleDateFormat("yyyy-MM-dd");
        Transaction tx = null;
        try
        {
            PrintWriter out = response.getWriter();
            Session session = HibernateUtil.getSessionFactory().getCurrentSession();
            tx = session.beginTransaction();

            response.setContentType(CONTENT_TYPE);
            out.println("<html><head><title>Event Manager</title></head><body>");

            if ("store".equals(request.getParameter("action")))
            {
                String eventTitle = request.getParameter("eventTitle");
                String eventDate = request.getParameter("eventDate");
                if ("".equals(eventTitle) || "".equals(eventDate))
                {
                    out.println("<b><i>Please enter event title and date.</i></b>");
                }else
                {
                    createAndStoreEvent(eventTitle, dateFormatter.parse(eventDate));
                    out.println("<b><i>Added event.</i></b>");
                }
            }
            printEventForm(out);
            listEvents(out, dateFormatter);

            out.println("</body></html>");
            out.flush();
            out.close();

            tx.commit();
        }
        catch (Exception ex)
        {
            if (tx != null)
            {
                tx.rollback();
            }
            throw new ServletException(ex);
        }
    }

    private void printEventForm(PrintWriter out) {
        out.println("<h2>Add new event:</h2>");
        out.println("<form>");
        out.println("Title: <input name='eventTitle' length='50'/><br/>");
        out.println("Date (e.g. 2008-11-18): <input name='eventDate' length='10'/><br/>");
        out.println("<input type='submit' name='action' value='store'/>");
        out.println("</form>");
    }

    private void listEvents(PrintWriter out, SimpleDateFormat dateFormatter) {
        List result = HibernateUtil.getSessionFactory().getCurrentSession().createCriteria(Event.class).list();
        if (result.size() > 0)
        {
            out.println("<h2>Events in database:</h2>");
            out.println("<table border='1'>");
            out.println("<tr>");
            out.println("<th>Event Title</th>");
            out.println("<th>Event Date</th>");
            out.println("</tr>");
            for (Iterator it = result.iterator(); it.hasNext(); )
            {
                Event event = (Event) it.next();
                out.println("<tr>");
                out.println("<td>" + event.getTitle() + "</td>");
                out.println("<td>" + dateFormatter.format(event.getDate()) + "</td>");
                out.println("</tr>");
            }
            out.println("</table>");
        }
    }

    protected void createAndStoreEvent(String title, Date theDate) {
        Event theEvent = new Event();
        theEvent.setTitle(title);
        theEvent.setDate(theDate);
        HibernateUtil.getSessionFactory().getCurrentSession().save(theEvent);
    }
}

For all code please email to : caishaojiang@gmail.com

posted @ 2008-03-05 18:13 Carl 阅读(3530) | 评论 (1) | 编辑收藏

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