1
@Stateless
2
public class JMSReceiveBean implements JMSReceiveRemote {
3
4 @Resource(name = "jms/Queue")
5 private Queue queue;
6 @Resource(name = "jms/ConnectionFactory")
7 private ConnectionFactory queueFactory;
8
9
private void receiveJMSMessageFromQueue() throws Exception {
10 Connection connection = null;
11 Session session = null;
12 connection = queueFactory.createConnection();
13 session = connection.createSession(false, javax.jms.Session.AUTO_ACKNOWLEDGE);
14 MessageConsumer consumer = session.createConsumer(queue);
15 consumer.setMessageListener(new MessageListener() {
16
17 public void onMessage(Message message) {
18 TextMessage msg = (TextMessage) message;
19 try {
20 String txt = msg.getText();
21 Logger.getLogger(JMSReceiveBean.class.getName()).log(Level.SEVERE, txt);
22 } catch (Exception ex) {
23 ex.printStackTrace();
24
}
25 }
26 });
27
28 connection.start();
29 }
30
31 public void receiveMessage() {
32 try {
33 receiveJMSMessageFromQueue();
34 } catch (Exception ex) {
35 Logger.getLogger(JMSReceiveBean.class.getName()).log(Level.SEVERE, null, ex);
36 }
37 }
38
}
@Stateless2
public class JMSReceiveBean implements JMSReceiveRemote {
3
4
@Resource(name = "jms/Queue")5
private Queue queue;6
@Resource(name = "jms/ConnectionFactory")7
private ConnectionFactory queueFactory;8
9
private void receiveJMSMessageFromQueue() throws Exception {
10
Connection connection = null;11
Session session = null;12
connection = queueFactory.createConnection();13
session = connection.createSession(false, javax.jms.Session.AUTO_ACKNOWLEDGE);14
MessageConsumer consumer = session.createConsumer(queue);15
consumer.setMessageListener(new MessageListener() {16
17
public void onMessage(Message message) {18
TextMessage msg = (TextMessage) message;19
try {20
String txt = msg.getText();21
Logger.getLogger(JMSReceiveBean.class.getName()).log(Level.SEVERE, txt);22
} catch (Exception ex) {23
ex.printStackTrace();24
}25
}26
});27
28
connection.start();29
}30
31
public void receiveMessage() {32
try {33
receiveJMSMessageFromQueue();34
} catch (Exception ex) {35
Logger.getLogger(JMSReceiveBean.class.getName()).log(Level.SEVERE, null, ex);36
}37
}38
}在15行消息使用者上設(shè)置了一個(gè)消息監(jiān)聽器，而沒有使用同步的receive方法。由于這是異步接收消息，程序并沒有處于阻塞狀態(tài)，為了避免在接收到消息之前連接終止，所以在28行之后并沒有關(guān)閉Connection，實(shí)際上這一步是不可缺少的。
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@Remotepublic interface HelloRemote { String sayHi(); void init(String name); void remove(); }接著開發(fā)有狀態(tài)會(huì)話bean：
@Statefulpublic class HelloBean implements HelloRemote { private String name; private Logger log = Logger.getLogger(this.getClass().getName()); public String sayHi() { return "Hi " + name; } public void init(String name) { this.name = name; } @PostConstruct public void postConstrut(){ log.info("create " + this); } @PreDestroy public void preDestory(){ log.info("destory " + this); } @PostActivate public void postActivate(){ log.info("activate " + this); } @PrePassivate public void prePassivate(){ log.info("passivate " + this); } @Remove public void remove(){ log.info("remove " + this); }}@Stateful注釋表明這是一個(gè)有狀態(tài)會(huì)話bean，其他的注釋是管理會(huì)話bean的生命周期。@PostConstruct注釋表明方法將會(huì)在bean實(shí)例化并完成依賴注入后由容器調(diào)用此方法；@PreDestory注釋表示方法會(huì)在容器刪除bean實(shí)例前由容器調(diào)用；以上兩個(gè)注釋所有的EJB（包括MDB）都可以用。@PostActivate注釋表示容器在激活bean后調(diào)用此方法；@PrePassivate注釋表示容器在鈍化bean前調(diào)用此方法；以上兩個(gè)注釋是有狀態(tài)會(huì)話bean所特有。@Remove注釋也是有狀態(tài)會(huì)話bean所特有，也是用戶唯一可以能控制的生命周期方法，一旦用戶在客戶端調(diào)用此方法，容器將刪除bean實(shí)例。接著看客戶端的測試代碼：
<% InitialContext ctx = new InitialContext(); HelloRemote helloBean = (HelloRemote)ctx.lookup(HelloRemote.class.getName()); helloBean.init("Tom"); out.println(helloBean.sayHi()); helloBean.remove();%>很簡單，只是多調(diào)用了一個(gè)remove方法。
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首先新建一個(gè)EJB模塊，然后在EJB模塊上新建一個(gè)WebService，代碼如下：
@WebService()@Stateless()public class Dog { @WebMethod(operationName = "ganr") public String ganr() { return "Wo-Wo-Wo"; }}Dog類同時(shí)使用了@WebService和@Stateless注釋，web服務(wù)端點(diǎn)只能是無狀態(tài)會(huì)話bean，web服務(wù)本身就是無狀態(tài)的。我們還用@WebMethod注釋向Web服務(wù)客戶端公開了一個(gè)ganr方法，完成后打包部署。
接著我們創(chuàng)建一個(gè)Web模塊，然后在Web項(xiàng)目上右鍵，選新建--Web服務(wù)客戶端，指定項(xiàng)目或者WSDL url。接著新建一個(gè)Servlet，然后右鍵調(diào)用Web服務(wù)操作，我們找到Dog服務(wù)的garn方法點(diǎn)確定，代碼自動(dòng)生成：
@WebServiceRef(wsdlLocation = "http://localhost:8080/DogService/Dog?wsdl") private DogService service;@WebServiceRef注釋聲明了一個(gè)到Web服務(wù)的引用
try { // Call Web Service Operation ejb.Dog port = service.getDogPort(); // TODO process result here java.lang.String result = port.ganr(); out.println("Result = " + result); } catch (Exception ex) { // TODO handle custom exceptions here }service.getDogPort()方法獲取到服務(wù)的一個(gè)代理，也稱為端口。接著看jsp：
<% try { ejb.DogService service = new ejb.DogService(); ejb.Dog port = service.getDogPort(); // TODO process result here java.lang.String result = port.ganr(); out.println("Result = "+result); } catch (Exception ex) { // TODO handle custom exceptions here } %>發(fā)現(xiàn)只有一點(diǎn)點(diǎn)不同，完成后部署web應(yīng)用并運(yùn)行測試。
我們還可以通過一個(gè)現(xiàn)有的會(huì)話Bean創(chuàng)建Web服務(wù)，還是拿HelloWorld舉例，首先創(chuàng)建一個(gè)遠(yuǎn)程接口：
@Remotepublic interface HelloRemote { String sayHi(String name);}再創(chuàng)建一個(gè)無狀態(tài)會(huì)話bean，先已經(jīng)說過了，只能是無狀態(tài)會(huì)話bean：
@Statelesspublic class HelloBean implements HelloRemote { public String sayHi(String name) { return "Hi " + name; }}然后新建一個(gè)Web服務(wù)Hello，只不過在彈出窗口中要選中“通過現(xiàn)有會(huì)話bean創(chuàng)建Web服務(wù)”單選框，并瀏覽指定HelloBean，代碼自動(dòng)完成：
@WebService()@Stateless()public class Hello { @EJB private HelloRemote ejbRef; // Add business logic below. (Right-click in editor and choose // "Web Service > Add Operation" @WebMethod(operationName = "sayHi") public String sayHi(@WebParam(name = "name")String name) { return ejbRef.sayHi(name); }}我們看到Hello服務(wù)里引用了一個(gè)HelloRemote接口，并發(fā)現(xiàn)遠(yuǎn)程接口公開的方法也被Hello服務(wù)公開，完成后打包部署EJB模塊。接著在Web服務(wù)客戶端測試，這和之前的步驟一樣，不再贅述，直接看代碼吧：
@WebServiceRef(wsdlLocation = "http://localhost:8080/HelloService/Hello?wsdl") private HelloService service; protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter(); try { try { // Call Web Service Operation ejb.Hello port = service.getHelloPort(); // TODO initialize WS operation arguments here java.lang.String name = "Tom"; // TODO process result here java.lang.String result = port.sayHi(name); out.println("Result = " + result); } catch (Exception ex) { // TODO handle custom exceptions here }
<% try { ejb.HelloService service = new ejb.HelloService(); ejb.Hello port = service.getHelloPort(); // TODO initialize WS operation arguments here java.lang.String name = "Tom"; // TODO process result here java.lang.String result = port.sayHi(name); out.println("Result = "+result); } catch (Exception ex) { // TODO handle custom exceptions here } %>發(fā)現(xiàn)一個(gè)問題，一個(gè)應(yīng)用上不能新建兩個(gè)Web服務(wù)客戶端（Dog和Hello），只有一個(gè)能有效使用（只找到一份工件），這是為什么？
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@WebService()public class Hello { @WebMethod(operationName = "sayHi") public String sayHi(@WebParam(name = "name")String name) { return "Hi " + name; }}
可以在源圖上右鍵，選Web服務(wù)--添加操作，也可以在設(shè)計(jì)圖上直接添加操作。@WebService標(biāo)注表明該類是一個(gè)web服務(wù)，展現(xiàn)給web服務(wù)客戶端的業(yè)務(wù)方法必須使用@WebMethod標(biāo)注來表示。打包部署該web應(yīng)用，web服務(wù)自動(dòng)會(huì)發(fā)布。可以在glassfish應(yīng)用服務(wù)器上找到該web服務(wù)，直接測試或者查看服務(wù)器生成的WSDL
<?xml version="1.0" encoding="UTF-8"?><!-- Published by JAX-WS RI at http://jax-ws.dev.java.net. RI's version is JAX-WS RI 2.1.3.1-hudson-417-SNAPSHOT. --><!-- Generated by JAX-WS RI at http://jax-ws.dev.java.net. RI's version is JAX-WS RI 2.1.3.1-hudson-417-SNAPSHOT. --><definitions xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:tns="http://webservice/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://schemas.xmlsoap.org/wsdl/" targetNamespace="http://webservice/" name="HelloService"> <types> <xsd:schema> <xsd:import namespace="http://webservice/" schemaLocation="http://localhost:8080/WebServiceApp/HelloService?xsd=1"> </xsd:import> </xsd:schema> </types> <message name="sayHi"> <part name="parameters" element="tns:sayHi"> </part> </message> <message name="sayHiResponse"> <part name="parameters" element="tns:sayHiResponse"> </part> </message> <portType name="Hello"> <operation name="sayHi"> <input message="tns:sayHi"> </input> <output message="tns:sayHiResponse"> </output> </operation> </portType> <binding name="HelloPortBinding" type="tns:Hello"> <soap:binding transport="http://schemas.xmlsoap.org/soap/http" style="document"> </soap:binding> <operation name="sayHi"> <soap:operation soapAction=""> </soap:operation> <input> <soap:body use="literal"> </soap:body> </input> <output> <soap:body use="literal"> </soap:body> </output> </operation> </binding> <service name="HelloService"> <port name="HelloPort" binding="tns:HelloPortBinding"> <soap:address location="http://localhost:8080/WebServiceApp/HelloService"> </soap:address> </port> </service></definitions>
也可以編寫客戶端測試，新建一個(gè)普通的java項(xiàng)目，在項(xiàng)目上右鍵，選擇新建--Web服務(wù)客戶端，在彈出窗口中指定WebService項(xiàng)目或者WSDL url，點(diǎn)擊完成。在源代碼上右鍵，選擇Web服務(wù)客戶端資源--調(diào)用Web服務(wù)操作，在彈出窗口中選擇sayHi操作，點(diǎn)確定，測試代碼自動(dòng)生成：
public class Main { public static void main(String[] args) { try { webservice.HelloService service = new webservice.HelloService(); webservice.Hello port = service.getHelloPort(); java.lang.String name = "Tom"; java.lang.String result = port.sayHi(name); System.out.println("Result = " + result); } catch (Exception ex) { // TODO handle custom exceptions here } }}運(yùn)行該客戶端，結(jié)果將會(huì)輸出
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@Remotepublic interface HelloRemote { String sayHi(String name);}第二個(gè)接口：
@Remotepublic interface HelloRemote1 { String sayBye(String name);}接下來寫會(huì)話bean，同時(shí)實(shí)現(xiàn)以上兩個(gè)接口：
@Stateless(mappedName="hello")public class HelloBean implements HelloRemote, HelloRemote1 { public String sayHi(String name) { return "Hi " + name; } public String sayBye(String name) { return "Bye " + name; } }注意這里用到了mappedName元素，這個(gè)很關(guān)鍵。把EJB模塊打包部署，接下來在遠(yuǎn)程客戶端測試，先寫Servlet：
@EJB(mappedName="hello#ejb.HelloRemote1") private HelloRemote1 helloBean1; @EJB(mappedName="hello#ejb.HelloRemote") private HelloRemote helloBean;注意@EJB標(biāo)注里也使用了mappedName元素，值的樣式是：JNDI名#包名.接口名。再看Jsp：
<% InitialContext ctx = new InitialContext(); HelloRemote helloBean = (HelloRemote)ctx.lookup("hello#ejb.HelloRemote"); out.println(helloBean.sayHi("Tom")); HelloRemote1 helloBean1 = (HelloRemote1)ctx.lookup("hello#ejb.HelloRemote1"); out.println("<br>" + helloBean1.sayBye("Tom"));%>和Servlet中的一樣
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首先定義一個(gè)遠(yuǎn)程接口：
@Remotepublic interface HelloRemote { String sayHi(String name);}第一個(gè)實(shí)現(xiàn)：
@Stateless(mappedName="hello")public class HelloBean implements HelloRemote { public String sayHi(String name) { return "Hi " + name; }}第二個(gè)實(shí)現(xiàn)：
@Stateless(mappedName="hello2")public class HelloBean2 implements HelloRemote{ public String sayHi(String name) { return "Hello " + name; }}兩個(gè)無狀態(tài)會(huì)話bean實(shí)現(xiàn)了同一個(gè)遠(yuǎn)程接口，但它們的mappedName不一樣，還有它們各自重寫了sayHi業(yè)務(wù)方法。部署EJB模塊然后測試，首先是Servlet：
@EJB(mappedName="hello2") private HelloRemote helloBean2; @EJB(mappedName="hello") private HelloRemote helloBean;然后是JSP：
<% InitialContext ctx = new InitialContext(); HelloRemote helloBean = (HelloRemote)ctx.lookup("hello"); out.println(helloBean.sayHi("Tom")); HelloRemote helloBean2 = (HelloRemote)ctx.lookup("hello2"); out.println("<br>" + helloBean2.sayHi("Tom"));%>呵呵，遠(yuǎn)程調(diào)用也實(shí)現(xiàn)了多態(tài)
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@Localpublic interface MessageLocal { String getMessage(); }接著編寫一個(gè)會(huì)話bean實(shí)現(xiàn)該接口：
@Statelesspublic class MessageBean implements MessageLocal { public String getMessage() { return "Hello world"; } }然后創(chuàng)建一個(gè)遠(yuǎn)程接口：
@Remotepublic interface HelloRemote { String welcome(); }編寫一個(gè)會(huì)話bean實(shí)現(xiàn)該接口：
@Statelesspublic class HelloBean implements HelloRemote { @EJB private MessageLocal messageBean; public String welcome() { return messageBean.getMessage(); } }在遠(yuǎn)程對象里聲明了一個(gè)本地接口的引用，并嘗試在遠(yuǎn)程方法當(dāng)中調(diào)用本地接口的本地方法。這些都沒問題，打包部署成功。
<% InitialContext ctx = new InitialContext(); HelloRemote helloBean = (HelloRemote)ctx.lookup(HelloRemote.class.getName()); out.println(helloBean.welcome());%>在遠(yuǎn)程客戶端的代碼如此，看起來一切正常，不過在部署WEB模塊的時(shí)候報(bào)異常：正在域中部署應(yīng)用程序 失敗；為模塊 [EjbWebClient] 裝入部署描述符時(shí)出錯(cuò) -- Cannot resolve reference Unresolved Ejb-Ref ejb.HelloBean/messageBean@jndi: @null@ejb.MessageLocal@Session@null
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我們先定義遠(yuǎn)程接口：
@Remotepublic interface HelloRemote { String sayHi(String name); String sayByeBye(String name); }接著定義本地接口：
@Localpublic interface HelloLocal { String sayBye(String name); }然后編寫一個(gè)會(huì)話bean同時(shí)實(shí)現(xiàn)兩個(gè)接口：
@Statelesspublic class HelloBean implements HelloRemote, HelloLocal { public String sayHi(String name) { return "Hi " + name; } public String sayBye(String name) { return "Bye " + name; } public String sayByeBye(String name) { return sayBye(name); } }那么，這還是一個(gè)無狀態(tài)會(huì)話bean，不過即可以遠(yuǎn)程訪問，也可以本地訪問。
<% InitialContext ctx = new InitialContext(); HelloRemote helloBean = (HelloRemote)ctx.lookup(HelloRemote.class.getName()); out.println(helloBean.sayHi("Tom")); out.println("<br>" + helloBean.sayByeBye("Tom"));%>遠(yuǎn)程訪問只能獲得遠(yuǎn)程接口的代理，然后調(diào)用遠(yuǎn)程業(yè)務(wù)方法。在遠(yuǎn)程客戶端是無法獲得本地接口的引用，更別說訪問本地方法了。
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