Thực hành EJB (Enterprise Java Bean) Lab 6 + 7

IT Research Department @BKAP 2015 Page 1 / 27Lab 06 - 07 Introduction to Messaging Interceptors and Dependency Injection Mục tiêu - Tạo và gửi một message đến một JMS Resource - Clien

IT Research Department @BKAP 2015 Page 1 / 27

Lab 06 - 07 Introduction to Messaging Interceptors and Dependency Injection

Mục tiêu

- Tạo và gửi một message đến một JMS Resource

- Client nhận một message được lưu trữ trên JMS Resource

- Tạo và cấu hình Interceptors

- Thực thi các Interceptors

Phần I Bài tập step by step

Bài 4.1 Xây dựng một JSF Web Application đặt lịch họp và thông báo đến tất cả các thành viên lịch họp đó

Step 1: Tạo một JSF Web Application tên là MeetingMessenger

 File  New  Java Web  WebApplication

 Name and Location: Project Name  MeetingMessenger

 Frameworks: JavaServer Faces

Step 2: Tạo một JMS Resource

 RC MeetingMessenger  New  GlassFish  JMS Resource

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 Sau khi hoàn thành, một JMS Resource được tạo và thông tin của nó được lưu trên file glassfish-resources.xml

<admin-object-resource enabled="true" jndi-name="jms/meetingMessQueue" object-type="user"

res-adapter="jmsra" res-type="javax.jms.Queue">

 RC MeetingMessenger  New  GlassFish  JMS Resource

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 Sau khi hoàn thành, Một JMS Resource Connection Factory được tạo và thông tin của

nó được lưu trong file glassfish-resource.xml

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE resources PUBLIC "-//GlassFish.org//DTD GlassFish Application Server 3.1 Resource Definitions//EN"

"http://glassfish.org/dtds/glassfish-resources_1_5.dtd">

<resources>

<admin-object-resource enabled="true" jndi-name="jms/meetingMessQueue" object-type="user"

res-adapter="jmsra" res-type="javax.jms.Queue">

max-wait-time-</resources>

Step 4: Tạo một JSF Managed Bean đặt tên JMSProducerBean trong package bean

 RC Source Packages  New  JavaServer Faces  JSF Managed Bean

 Viết code JMSProducerBean.java

package bean;

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public class JMSProducerBean {

//Them meetingMessQueue reference den jms/meetingMessQueue

@Resource(mappedName = "jms/meetingMessQueue")

private Queue meetingMessQueue;

//Khai bao message truyen thong bao

private String message;

public JMSProducerBean() {

}

//Getter and setter

public String getMessage() {

//phuong thuc send message

public void send() throws NamingException, JMSException {

InitialContext initContext = new InitialContext();

FacesContext facesContext = FacesContext.getCurrentInstance();

ConnectionFactory factory = (ConnectionFactory) initContext.lookup("jms/meetingMessQueueFactory");

Destination destination = (Destination) initContext.lookup("jms/meetingMessQueue");

initContext.close();

//Tao cac doi tuong JMS

Connection connection = factory.createConnection();

Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);

MessageProducer sender = session.createProducer(destination);

//Gui message

TextMessage msg = session.createTextMessage(message);

<h:outputLabel value="Message: "/>

<h:inputText id="message" value="#{jMSProducerBean.message}" size="30"/>

<h:commandButton id="Send" value="Send Message" action="#{jMSProducerBean.send()}"/>

<h:messages globalOnly="true"/>

</h:form>

</h:body>

</html>

Step 6: Build and Run Application

Step 7: Kiểm tra JMS Resource lưu trữ trên Server

 Services  Servers  GlassFish Server  View Domain Admin Console

 Common Tasks  Server (Admin Server) JMS Physical Destinations

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Step 8: Tạo EJBModule để nhận các message từ JMS Resource

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Step 9: Tạo Message-Driver Been

 ClientMessage  New  Other EnterpriseBeans  Message-Driver Bean

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@ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Queue"),

@ActivationConfigProperty(propertyName = "destinationLookup", propertyValue = "jms/meetingMessQueue") })

public class JMSConsumerBean implements MessageListener {

public JMSConsumerBean() {

}

@Override

public void onMessage(Message message) {

if (message instanceof TextMessage) {

TextMessage msg = (TextMessage) message;

try {

System.out.println("Received message: " + msg.getText());

} catch (JMSException ex) {

Logger.getLogger(JMSConsumerBean.class.getName()).log(Level SEVERE, null, ex);

Bài 4.2 Xây dựng ứng dụng chat gồm các room chat để user có thể join vào các room chat và tính

số lượng user join vào mỗi phòng

Step 1: Tạo một ứng dụng Enterprise với tên là ChatApplication

 File  New Project  Java EE  Enterprise Application

 Name: ChatApplication

 Server and Settings

 Server: GlassFish Server

 Create EJB Module

 Create Web Application Module

 Sau khi hoàn thành:

Step 2: Tạo lớp java ChatRoomStats trong package data để quản lý phòng chat, số người

trong phòng chat, thời gian tham gia phòng chat

 ChatApplication-ejb  New  Other  Java  Java Class

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public class ChatRoomStats {

//Khai bao ten phong chat la bien chatRoom

private String chatRoom;

//Khai bao so luong nguowi trong phong chat la bien personCount

private int personCount;

//Khai bao so thoi gian tham gia phong chat la bien totalTime

private long totalTime;

//Tao constructor

public ChatRoomStats(String chatRoom) {

this.chatRoom = chatRoom;

}

//Getter va Setter cac bien

public String getChatRoom() {

//Phuong thuc tang so luong nguoi tham gia phong chat khi co nguoi join vao

public void increment() {

this.personCount += 1;

}

//Phuong thuc tinh so thoi gian tham gia

public void increaseTotalTime(long time) {

this.totalTime += time;

}

}

Step 3: Tạo lớp java ApplicationStats trong package datatrên cơ sở Singleton pattern để

khởi tạo đối tượng ChatRoomStats

 ChatApplication-ejb  New  Other  Java  Java Class

public class ApplicationStats {

//Khai bao bien Singleton

private static ApplicationStats instance;

//Khai bao danh sach ChatRoomStats

private static List<ChatRoomStats> chatRoomStats = new ArrayList<>();

//Constructor

public ApplicationStats() {

}

//Phuong thuc khoi tao instance

public static ApplicationStats getInstance() {

//Phuong thuc tinh so nguoi chat

public void inscrementCount(String chatRoom){

for (ChatRoomStats room : chatRoomStats) {

//Phuong thuc tinh so nguoi chat trong 1 thoi gian

public void recordTime(String chatRoom, long time){

for (ChatRoomStats room : chatRoomStats) {

if (room.getChatRoom().equals(chatRoom)) {

room.increaseTotalTime(time);

break;

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}

}

}

//Phuong thuc get List Chat Room

public List<ChatRoomStats> getChatRoomStats(){

@LocalBean

public class ChatRoomBean {

public void joinChatRoom(String chatRoom) {

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public class ChatRoomInterceptor {

//Phuong thuc xu ly truoc khi khoi tao session bean

@PostConstruct

public void initialiseChatRoom(InvocationContext context) {

System.out.println("PostConstruct - initialising Chat Rooms");

List<ChatRoomStats> list = ApplicationStats.getInstance().getChatRoomStats();

//Them cac phong chat vao list

list.add(new ChatRoomStats(("Business")));

list.add(new ChatRoomStats("Family"));

}

//Phuong thuc xu ly truong khi huy session bean

@PreDestroy

public void preDestroy(InvocationContext context) {

System.out.println("PreDestroy - Clearing Chat Room");

ApplicationStats.getInstance().getChatRoomStats().clear();

}

}

Step 6: Tạo lớp java có tên HitCounterInterceptor trong package interceptorpack để đếm

số người join vào room chat

public class HitCounterInterceptor {

//Phuong thuc thuc thi truoc va sau khi xu ly nghiep vu

@AroundInvoke

public Object incrementHitCount(InvocationContext context) throws Exception{

System.out.println("HitCounterInterceptor - Start");

//lay Chat Room

String chatRoom = (String) context.getParameters()[0];

//Tang so luong nguoi chat trong room

ApplicationStats.getInstance().inscrementCount(chatRoom);

Object result = context.proceed();

System.out.println("HitCounterInterceptor - Terminate");

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public class TimerInterceptor {

public Object recordPerfTime(InvocationContext context) throws Exception {

System.out.println("PerformanceMethodInterceptor - Start");

String chatRoom = (String) context.getParameters()[0];

long startTime = System.currentTimeMillis();

Object result = context.proceed();

long endTime = System.currentTimeMillis();

ApplicationStats.getInstance().recordTime(chatRoom, endTime - startTime);

System.out.println("PerformanceMethodInterceptor - Terminate");

System.out.println("New person joined the Chat Room " + chatRoom); }

Step 9: Tạo servlet tên là ChatServlet trong package servlet thực thi interceptor

 ChatApplication-war  New  Other  Web  Servlet

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public class ChatServlet extends HttpServlet {

//goi Enterprice session bean

* @param request servlet request

* @param response servlet response

* @throws ServletException if a servlet-specific error occurs

* @throws IOException if an I/O error occurs

*/

protected void processRequest(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html;charset=UTF-8");

//Lay ten phong chat tu request

String chatRoom = request.getParameter("ChatRoom");

try (PrintWriter out = response.getWriter()) {

//Kiem tra neu trang duoc load hoac join vao room

if (chatRoom != null && !chatRoom.isEmpty()) {

//Thuc thi phuong thuc interceptor

//Form hien thi cho user

out.println("<form name='ChatStats' action='ChatServlet' method='POST'>");

out.println("Chat Room: <select name='ChatRoom'>");

out.println("<option value='Business'>Business</option>");

out.println("<option value='Family'>Family</option>");

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out.println("</select>");

out.println("<input type='submit' value='Join'/>");

out.println("<br/><hr>");

out.println("<h2>Chat Statistics</h2>");

//Lay list ChatRoomStats

List<ChatRoomStats> stats = chatRoomBean.getChatRoomStats();

for (ChatRoomStats room : stats) {

out.println("Chat Room - " + room.getChatRoom());

out.println("<ul><li>Number of people - " + room.getPersonCount() + "</li>");

out.println("<li> Total time taken (in mill sec) - " + room.getTotalTime());

* @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 {

* @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 {

public String getServletInfo() {

return "Short description";

}// </editor-fold>

}

 Ứng dụng sau khi hoàn thành

Step 10: Build and Run Application

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