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以下のコードを参照してください。メッセージ - 連続ループ
package com.w0051977.dao;
import javax.annotation.Resource;
import javax.ejb.ActivationConfigProperty;
import javax.ejb.MessageDriven;
import javax.ejb.MessageDrivenContext;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.ObjectMessage;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import com.w0051977.model.Student;
/**
*
* @author
*/
@MessageDriven(activationConfig = {
@ActivationConfigProperty(propertyName = "destinationLookup", propertyValue = "jms/StudentMessage"),
@ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Queue")
})
public class StudentMessage implements MessageListener {
@Resource
private MessageDrivenContext mdc;
@PersistenceContext(unitName = "CRUDWebAppPU")
private EntityManager em;
public StudentMessage() {
}
@Override
public void onMessage(Message message) {
ObjectMessage msg = null;
try {
if (message instanceof ObjectMessage) {
msg = (ObjectMessage) message;
Student s1 = (Student) msg.getObject();
save(s1);
}
} catch (JMSException e) {
e.printStackTrace();
mdc.setRollbackOnly();
} catch (Throwable te) {
te.printStackTrace();
}
}
public void save(Object object) {
em.persist(object);
}
}
私は、このクラスを追加し、Netbeansの7.4にGlassFishサーバーを再起動します。 Glassfishログは、OnMessageが連続ループで実行されていることを示し、Netbeansがクラッシュするまで実行を続けます。 Studentオブジェクトには、このサーブレットからフィードされる値が含まれています。
package com.w0051977.controller;
import java.io.IOException;
import java.io.PrintWriter;
import javax.annotation.Resource;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.JMSException;
import javax.jms.MessageProducer;
import javax.jms.ObjectMessage;
import javax.jms.Queue;
import javax.jms.Session;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.w0051977.model.Student;
/**
*
* @author 3212627
*/
@WebServlet(name = "ServletAddStudentMessageBean", urlPatterns = {"/ServletAddStudentMessageBean"})
public class ServletAddStudentMessageBean extends HttpServlet {
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code>
* methods.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Resource(mappedName="jms/StudentMessageFactory")
private ConnectionFactory connectionFactory;
@Resource(mappedName="jms/StudentMessage")
private Queue queue;
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
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
Student s1 = new Student();
s1.setFirstName("Fred");
s1.setLastName("Bloggs");
s1.setYearLevel(3);
message.setObject(s1);
messageProducer.send(message);
messageProducer.close();
connection.close();
response.sendRedirect("StudentInfo");
} catch (JMSException ex) {
ex.printStackTrace();
}
PrintWriter out = response.getWriter();
out.println("Servlet PostMessage at " + request.getContextPath() + "</h1>");
// The following code adds the form to the web page
out.println("<form>");
out.println("Title: <input type='text' name='title'><br/>");
out.println("Message: <textarea name='body'></textarea><br/>");
out.println("<input type='submit'><br/>");
out.println("</form>");
out.println("</body>");
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Handles the HTTP <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}
なぜ連続ループがありますか？私はサーブレットを削除していますが、依然としてループが継続しているようです。