Question

我创建了一个Java EE 6应用程序并实现了插入，更新和删除。他们有时工作正常，但突然停止工作。我调试了，我发现有时候JMS消息不会从servlet传递到消息驱动的bean。因此，在这种情况下，我的数据不会被插入，更新或删除。这是使用持久性和javaDB的Java EE应用程序的正常行为吗？或者我犯了错误？

在servlet中我有这个：

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    response.setContentType("text/html;charset=UTF-8");
    String id=request.getParameter("id");
    String name=request.getParameter("name");
    String description=request.getParameter("description");
    if ((name!=null) && (description!=null)) {
        try {
            Connection connection = connectionFactory.createConnection();
            Session session = connection.createSession(false,Session.AUTO_ACKNOWLEDGE);
            MessageProducer messageProducer = session.createProducer(queue);
            ObjectMessage message = session.createObjectMessage();
            // here we create NewsEntity, that will be sent in JMS message
            AuthorEntity e = new AuthorEntity();
            e.setAuthorName(name);
            e.setDescription(description);
            message.setObject(e);
            messageProducer.send(message);
            messageProducer.close();
            connection.close();
            response.sendRedirect("ListAuthors");
        } catch (JMSException ex) {
            ex.printStackTrace();
        }
    }



    PrintWriter out = response.getWriter();
    try {
        /*
         * TODO output your page here. You may use following sample code.
         */
        out.println("<html>");
        out.println("<head>");
        out.println("<title>New Author</title>");            
        out.println("</head>");
        out.println("<body>");
        out.println("<h1>New Author</h1>");
        int n=authorEntityFacade.count();
        out.println("<form>");
        out.println("Author ID      : <input type='number' name='id' value='"+(n+1)+"'><br/>");
        out.println("Author Name    : <input type='text' name='name'><br/>");
        out.println("Description    : <textarea name='description'></textarea><br/>");
        out.println("<input type='submit'><br/>");
        out.println("</form>");

        out.println("</body>");
        out.println("</html>");
    } finally {            
        out.close();
    }
}

这里我准备了jms消息并发送到消息驱动的bean。

在消息驱动的bean中，我有：

@Resource
private MessageDrivenContext mdc;
@PersistenceContext(unitName = "IT11032748_Book_Catalogue-ejbPU")
private EntityManager em;

public NewAuthor() {
}

@Override
public void onMessage(Message message) {
    ObjectMessage objectMessage=null;
    try{
        if(message instanceof ObjectMessage){
            objectMessage=(ObjectMessage)message;
            AuthorEntity author=(AuthorEntity)objectMessage.getObject();
            save(author);
        }
    }catch(JMSException e){
        e.printStackTrace();
        mdc.setRollbackOnly();
    }catch(Throwable te){
        te.printStackTrace();
    }
}

public void save(Object object) {
    em.persist(object);
}

在这里，我接受消息并插入或者使用watever。

调试时，所有值都已正确设置，并且还会发送servlet消息。但是，调试点有时不会移动到消息驱动的bean：（

为什么Java EE 6应用程序不实时更新接口

0 个答案: