我们来实现处理请求以及渲染页面的工作。

// Write HTML header
PrintWriter out = response.getWriter();
out.println("<html><head><title>Event Manager</title></head><body>");

// Handle actions
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>");
    }
}

// Print page
printEventForm(out);
listEvents(out, dateFormatter);

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

listEvents()方法使用绑定到当前线程的Hibernate Session来执行查询:

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>");
    }
}

最后,store动作会被导向到createAndStoreEvent()方法,它也使用当前线程的Session:

protected void createAndStoreEvent(String title, Date theDate) {
    Event theEvent = new Event();
    theEvent.setTitle(title);
    theEvent.setDate(theDate);

    HibernateUtil.getSessionFactory()
                    .getCurrentSession().save(theEvent);
}

大功告成,这个servlet写完了。Hibernate会在单一的SessionTransaction中处理到达的servlet请求。如同在前面的独立应用程序中那样,Hibernate可以自动的把这些对象绑定到当前运行的线程中。这给了你用任何你喜欢的方式来对代码分层及访问SessionFactory的自由。通常,你会用更加完备的设计,把数据访问代码转移到数据访问对象中(DAO模式)。请参见Hibernate Wiki,那里有更多的例子。