一、ActiveMQ

1.1  ActiveMQ

ActiveMQ是Apache所提供的一个开源的消息系统,完全采用Java来实现,因此,它能很好地支持J2EE提出的JMS(Java Message Service,即Java消息服务)规范。JMS是一组Java应用程序接口,它提供消息的创建、发送、读取等一系列服务。JMS提供了一组公共应用程序接口和响应的语法,类似于Java数据库的统一访问接口JDBC,它是一种与厂商无关的API,使得Java程序能够与不同厂商的消息组件很好地进行通信。

 

 

1.2  Java Message Service(JMS)

JMS支持两种消息发送和接收模型。

  • 一种称为P2P(Ponit to Point)模型(点对点一对一),即采用点对点的方式发送消息。P2P模型是基于队列的,消息生产者发送消息到队列,消息消费者从队列中接收消息,队列的存在使得消息的异步传输称为可能,P2P模型在点对点的情况下进行消息传递时采用。

  • 另一种称为Pub/Sub(Publish/Subscribe,即发布-订阅)模型,发布-订阅模型定义了如何向一个内容节点发布和订阅消息,这个内容节点称为topic(主题)。主题可以认为是消息传递的中介,消息发布这将消息发布到某个主题,而消息订阅者则从主题订阅消息。主题使得消息的订阅者与消息的发布者互相保持独立,不需要进行接触即可保证消息的传递,发布-订阅模型在消息的一对多广播时采用。

1.3  JMS术语

  1. Provider/MessageProvider:生产者

  2. Consumer/MessageConsumer:消费者

  3. PTP:Point To Point,点对点通信消息模型

  4. Pub/Sub:Publish/Subscribe,发布订阅消息模型

  5. Queue:队列,目标类型之一,和PTP结合

  6. Topic:主题,目标类型之一,和Pub/Sub结合

  7. ConnectionFactory:连接工厂,JMS用它创建连接

  8. Connnection:JMS Client到JMS Provider的连接

  9. Destination:消息目的地,由Session创建

  10. Session:会话,由Connection创建,实质上就是发送、接受消息的一个线程,因此生产者、消费者都是 Session创建的

1.4  ActiveMQ应用场景

类似送快递,快递员(producer)将快递(Message)放到指定地点(destination)后,就可以离开了,拿快递的人(customer)在接收到通知后,到指定地点(destination)去取快递(Message)就可以了。当然,取快递时可能要进行身份验证,这就涉及到创建连接(connection)时,需要指定用户名和密码了。还有就是,实际生活中,当快递员把快递放好之后,照理说应该通知客户去哪里取快递,而ActiveMq帮我们做好了一切,通知的工作Activemq会帮我们实现,而无需我们亲自编码通知消费者,生产者只需要将Message放到Mq中即可,通知消费者的工作,mq会帮我们处理

用途就是用来处理消息,也就是处理JMS在大型电子商务类网站,如京东、淘宝、去哪儿等网站有着深入的应用,队列的主要作用是消除高并发访问高峰,加快网站的响应速度。

在不使用消息队列的情况下,用户的请求数据直接写入数据库,高发的情况下,会对数据库造成巨大的压力,同时也使得系统响应延迟加剧,但使用队列后,用户的请求发给队列后立即返回。

1.5  ActiveMQ下载

 

1.6  启动

/apache-activemq-5.15.3/bin/win64/目录下双击activemq.bat文件,在浏览器中输入http://localhost:8161/admin/, 用户名和密码输入admin即可

 

 

二、Srping+ActiveMQ应用实例

2.1  项目结构

 

2.2  导入maven依赖,pom.xml文件

   1 <?xml version="1.0" encoding="UTF-8"?>
  2 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  3   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  4   <modelVersion>4.0.0</modelVersion>
  5 
  6   <groupId>www.cnblogs.com.hongmoshu</groupId>
  7   <artifactId>test_actmq</artifactId>
  8   <version>0.0.1-SNAPSHOT</version>
  9   <packaging>war</packaging>
 10   <name>test_actmq Maven Webapp</name>
 11   <url>http://www.example.com</url>
 12   
 13    <!-- 版本管理 -->
 14   <properties>
 15     <springframework>4.1.8.RELEASE</springframework>
 16   </properties>
 17  
 18 
 19    <dependencies>
 20    
 21      <!-- junit单元测试 -->
 22     <dependency>
 23       <groupId>junit</groupId>
 24       <artifactId>junit</artifactId>
 25       <version>4.11</version>
 26       <scope>test</scope>
 27     </dependency>
 28     
 29     <!-- JSP相关 -->
 30   <dependency>
 31     <groupId>jstl</groupId>
 32     <artifactId>jstl</artifactId>
 33     <version>1.2</version>
 34   </dependency>
 35   <dependency>
 36     <groupId>javax.servlet</groupId>
 37     <artifactId>servlet-api</artifactId>
 38     <scope>provided</scope>
 39     <version>2.5</version>
 40   </dependency>
 41 
 42      <!-- spring -->
 43     <dependency>
 44       <groupId>org.springframework</groupId>
 45       <artifactId>spring-core</artifactId>
 46       <version>${springframework}</version>
 47     </dependency>
 48     <dependency>
 49       <groupId>org.springframework</groupId>
 50       <artifactId>spring-context</artifactId>
 51       <version>${springframework}</version>
 52     </dependency>
 53     <dependency>
 54       <groupId>org.springframework</groupId>
 55       <artifactId>spring-tx</artifactId>
 56       <version>${springframework}</version>
 57     </dependency>
 58     <dependency>
 59       <groupId>org.springframework</groupId>
 60       <artifactId>spring-webmvc</artifactId>
 61       <version>${springframework}</version>
 62     </dependency>
 63     <dependency>
 64       <groupId>org.springframework</groupId>
 65       <artifactId>spring-jms</artifactId>
 66       <version>${springframework}</version>
 67     </dependency>
 68     
 69     <!-- xbean 如<amq:connectionFactory /> -->
 70     <dependency>
 71       <groupId>org.apache.xbean</groupId>
 72       <artifactId>xbean-spring</artifactId>
 73       <version>3.16</version>
 74     </dependency>
 75     
 76     <!-- activemq -->
 77     <dependency>
 78       <groupId>org.apache.activemq</groupId>
 79       <artifactId>activemq-core</artifactId>
 80       <version>5.7.0</version>
 81     </dependency>
 82     <dependency>
 83       <groupId>org.apache.activemq</groupId>
 84       <artifactId>activemq-pool</artifactId>
 85       <version>5.12.1</version>
 86     </dependency>
 87     
 88     <!-- gson -->
 89     <dependency>
 90       <groupId>com.google.code.gson</groupId>
 91       <artifactId>gson</artifactId>
 92       <version>1.7.1</version>
 93     </dependency>
 94     
 95       <!-- JSON -->
 96     <dependency>
 97         <groupId>net.sf.json-lib</groupId>
 98         <artifactId>json-lib</artifactId>
 99         <version>2.4</version>
100         <classifier>jdk15</classifier>
101     </dependency>
102     
103   </dependencies>
104 
105   <build>
106     <finalName>test_actmq</finalName>
107   
108   </build>
109 </project>


2.3 ActiveMQ的配置文件ActiveMQ.xml

  1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans xmlns="http://www.springframework.org/schema/beans"
 3        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4        xmlns:amq="http://activemq.apache.org/schema/core"
 5        xmlns:jms="http://www.springframework.org/schema/jms"
 6        xmlns:context="http://www.springframework.org/schema/context"
 7        xmlns:mvc="http://www.springframework.org/schema/mvc"
 8        xsi:schemaLocation="
 9         http://www.springframework.org/schema/beans
10         http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
11         http://www.springframework.org/schema/context
12         http://www.springframework.org/schema/context/spring-context-4.1.xsd
13         http://www.springframework.org/schema/mvc
14         http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd
15         http://www.springframework.org/schema/jms
16         http://www.springframework.org/schema/jms/spring-jms-4.1.xsd
17         http://activemq.apache.org/schema/core
18         http://activemq.apache.org/schema/core/activemq-core-5.12.1.xsd"
19 >
20 
21     <context:component-scan base-package="com.svse.service" />
22     <mvc:annotation-driven />
23 
24     <!-- jms.useAsyncSend=true 允许异步接收消息 -->
25     <amq:connectionFactory id="amqConnectionFactory"
26                            brokerURL="tcp://192.168.6.111:61616?jms.useAsyncSend=true"
27                            userName="admin"
28                            password="admin" />
29 
30     <!-- 配置JMS连接工 厂 -->
31     <bean id="connectionFactory"
32           class="org.springframework.jms.connection.CachingConnectionFactory">
33         <constructor-arg ref="amqConnectionFactory" />
34         <property name="sessionCacheSize" value="100" />
35     </bean>
36 
37     <!-- 定义消息队列名称(Queue) -->
38     <bean id="demoQueueDestination" class="org.apache.activemq.command.ActiveMQQueue">
39         <!-- 设置消息队列的名字 -->
40         <constructor-arg>
41             <value>Jaycekon</value>
42         </constructor-arg>
43     </bean>
44 
45     <!-- 配置JMS模板(Queue),Spring提供的JMS工具类,它发送、接收消息。 -->
46     <bean id="jmsTemplate" class="org.springframework.jms.core.JmsTemplate">
47         <property name="connectionFactory" ref="connectionFactory" />
48         <property name="defaultDestination" ref="demoQueueDestination" />
49         <property name="receiveTimeout" value="10000" />
50         <!-- true是topic,false是queue,默认是false,此处显示写出false -->
51         <property name="pubSubDomain" value="false" />
52         <!-- 消息转换器 -->    
53         <property name="messageConverter" ref="userMessageConverter"/>  
54     </bean>
55 
56      <!-- 类型转换器 -->    
57     <bean id="userMessageConverter" class="com.svse.util.ObjectMessageConverter"/>    
58 
59 
60     <!-- 配置消息队列监听者(Queue) -->
61      <bean id="queueMessageListener" class="com.svse.util.QueueMessageListener" /> 
62 
63     <!-- 显示注入消息监听容器(Queue),配置连接工厂,监听的目标是demoQueueDestination,***是上面定义的*** -->
64     <bean id="queueListenerContainer"
65           class="org.springframework.jms.listener.DefaultMessageListenerContainer">
66         <property name="connectionFactory" ref="connectionFactory" />
67         <property name="destination" ref="demoQueueDestination" />
68         <property name="messageListener" ref="queueMessageListener" />
69     </bean> 
70     
71 </beans>


2.4  Spring的配置文件 spring-mvc.xml

  1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans xmlns="http://www.springframework.org/schema/beans"
 3     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4     xmlns:context="http://www.springframework.org/schema/context"
 5     xmlns:mvc="http://www.springframework.org/schema/mvc"
 6     xsi:schemaLocation="http://www.springframework.org/schema/beans 
 7         http://www.springframework.org/schema/beans/spring-beans.xsd
 8         http://www.springframework.org/schema/context
 9         http://www.springframework.org/schema/context/spring-context-4.1.xsd
10         http://www.springframework.org/schema/mvc 
11         http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">
12          
13     <context:component-scan base-package="com.svse.controller" />
14     <mvc:annotation-driven />
15     <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
16         <property name="viewClass"
17             value="org.springframework.web.servlet.view.JstlView" />
18         <property name="prefix" value="/WEB-INF/views/" />
19         <property name="suffix" value=".jsp" />
20     </bean>
21      
22 </beans>


2.5  web.xml

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
 3          xmlns="http://xmlns.jcp.org/xml/ns/javaee" 
 4          xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" 
 5          id="WebApp_ID" version="3.1">
 6   <display-name>mydemo</display-name>
 7   
 8   <welcome-file-list>
 9     <welcome-file>index.jsp</welcome-file>
10   </welcome-file-list>
11   
12   <!-- 加载spring及active的配置文件,classpath为项目src下的路径 -->
13   <context-param>
14     <param-name>contextConfigLocation</param-name>
15     <param-value>
16           classpath:spring-mvc.xml;
17           classpath:ActiveMQ.xml;
18     </param-value>
19     </context-param>
20 
21 
22  <listener>
23     <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
24   </listener>
25 
26   <servlet>
27     <servlet-name>springMVC</servlet-name>
28     <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
29     <init-param>
30       <param-name>contextConfigLocation</param-name>
31       <param-value>classpath:spring-mvc.xml</param-value>
32     </init-param>
33     <load-on-startup>1</load-on-startup>
34   </servlet>
35   <servlet-mapping>
36     <servlet-name>springMVC</servlet-name>
37     <url-pattern>/</url-pattern>
38   </servlet-mapping>
39 
40   <!-- 处理编码格式 -->
41   <filter>
42     <filter-name>characterEncodingFilter</filter-name>
43     <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
44     <init-param>
45       <param-name>encoding</param-name>
46       <param-value>UTF-8</param-value>
47     </init-param>
48     <init-param>
49       <param-name>forceEncoding</param-name>
50       <param-value>true</param-value>
51     </init-param>
52   </filter>
53   <filter-mapping>
54     <filter-name>characterEncodingFilter</filter-name>
55     <url-pattern>/*</url-pattern>
56   </filter-mapping>
57   
58 </web-app>


2.6  实体类Users对象

  1 package com.svse.entity;
 2 import java.io.Serializable;
 3 
 4 public class Users implements Serializable{
 5 
 6     private String userId;
 7     private String userName;
 8     private String sex;
 9     private String age;
10     private String type;
11     
12     
13     public Users() {
14         super();
15     }
16     public Users(String userId, String userName, String sex, String age,
17             String type) {
18         super();
19         this.userId = userId;
20         this.userName = userName;
21         this.sex = sex;
22         this.age = age;
23         this.type = type;
24     }
25     public String getUserId() {
26         return userId;
27     }
28     public void setUserId(String userId) {
29         this.userId = userId;
30     }
31     public String getUserName() {
32         return userName;
33     }
34     public void setUserName(String userName) {
35         this.userName = userName;
36     }
37     public String getSex() {
38         return sex;
39     }
40     public void setSex(String sex) {
41         this.sex = sex;
42     }
43     public String getAge() {
44         return age;
45     }
46     public void setAge(String age) {
47         this.age = age;
48     }
49     public String getType() {
50         return type;
51     }
52     public void setType(String type) {
53         this.type = type;
54     }
55     @Override
56     public String toString() {
57         return "Users [userId=" + userId + ", userName=" + userName + ", sex="
58                 + sex + ", age=" + age + ", type=" + type + "]";
59     }
60     
61     
62 }


2.7  核心代码(生产者ProducerService)

  1 package com.svse.service;
 2 
 3 import javax.annotation.Resource;
 4 import javax.jms.Destination;
 5 import javax.jms.JMSException;
 6 import javax.jms.Message;
 7 import javax.jms.Session;
 8 
 9 import org.springframework.jms.core.JmsTemplate;
10 import org.springframework.jms.core.MessageCreator;
11 import org.springframework.stereotype.Service;
12 
13 import com.svse.entity.Users;
14 
15 @Service
16 public class ProducerService {
17 
18     @Resource(name="jmsTemplate")
19     private JmsTemplate jmsTemplate;
20     
21     
22     /**
23      * 向指定队列发送消息 (发送文本消息)
24      */
25     public void sendMessage(Destination destination,final String msg){
26         
27         jmsTemplate.setDeliveryPersistent(true);
28         
29         System.out.println(Thread.currentThread().getName()+" 向队列"+destination.toString()+"发送消息---------------------->"+msg);
30         jmsTemplate.send(destination, new MessageCreator() {
31             public Message createMessage(Session session) throws JMSException {
32                 return session.createTextMessage(msg);
33             }
34         });
35     }
36     
37     /**
38      * 向指定队列发送消息以对象的方式 (发送对象消息)
39      */
40     public void sendMessageNew(Destination destination,Users user){
41         System.out.println(Thread.currentThread().getName()+" 向队列"+destination.toString()+"发送消息---------------------->"+user);
42         jmsTemplate.convertAndSend(user);
43     }
44 
45     /**
46      * 向默认队列发送消息
47      */
48     public void sendMessage(final String msg){
49         String destination = jmsTemplate.getDefaultDestinationName();
50         System.out.println(Thread.currentThread().getName()+" 向队列"+destination+"发送消息---------------------->"+msg);
51         jmsTemplate.send(new MessageCreator() {
52             public Message createMessage(Session session) throws JMSException {
53                 return session.createTextMessage(msg);
54             }
55         });
56     }
57 }

 

2.8  核心代码(消费产者ConsumerService)

 1 package com.svse.service;
 2 
 3 import javax.annotation.Resource;
 4 import javax.jms.Destination;
 5 import javax.jms.JMSException;
 6 import javax.jms.ObjectMessage;
 7 import javax.jms.TextMessage;
 8 
 9 import net.sf.json.JSONObject;
10 
11 import org.springframework.jms.core.JmsTemplate;
12 import org.springframework.stereotype.Service;
13 
14 import com.svse.entity.Users;
15 
16 @Service
17 public class ConsumerService {
18 
19      @Resource(name="jmsTemplate")
20      private JmsTemplate jmsTemplate;
21      //接收文本消息
22      public TextMessage receive(Destination destination){
23             TextMessage textMessage = (TextMessage) jmsTemplate.receive(destination);
24             try{
25                 JSONObject json=JSONObject.fromObject(textMessage.getText());
26                 System.out.println("name:"+json.getString("userName"));
27                 System.out.println("从队列" + destination.toString() + "收到了消息:\t"
28                         + textMessage.getText());
29             } catch (JMSException e) {
30                 e.printStackTrace();
31             }
32             return textMessage;
33         }
34      //接收对象消息
35      public ObjectMessage receiveNew(Destination destination){
36              ObjectMessage objMsg=(ObjectMessage) jmsTemplate.receive(destination);
38              try{
39                 Users users= (Users) objMsg.getObject();
44                 System.out.println("name:"+users.getUserName());
47                 System.out.println("从队列" + destination.toString() + "收到了消息:\t"
48                         + users);
49             } catch (JMSException e) {
50                 e.printStackTrace();
51             }
52             return objMsg;
53         }
54 }


2,9). 核心代码(控制器ConsumerService)

   1 package com.svse.controller.mq;
  2 
  3 import java.io.IOException;
  4 import java.text.SimpleDateFormat;
  5 import java.util.Date;
  7 import javax.annotation.Resource;
  8 import javax.jms.DeliveryMode;
  9 import javax.jms.Destination;
 10 import javax.jms.JMSException;
 11 import javax.jms.ObjectMessage;
 12 import javax.jms.TextMessage;
 13 import javax.management.MBeanServerConnection;
 14 import javax.management.remote.JMXConnector;
 15 import javax.management.remote.JMXConnectorFactory;
 16 import javax.management.remote.JMXServiceURL;
 18 import org.springframework.stereotype.Controller;
 19 import org.springframework.web.bind.annotation.RequestMapping;
 20 import org.springframework.web.bind.annotation.RequestMethod;
 21 import org.springframework.web.bind.annotation.RequestParam;
 22 import org.springframework.web.servlet.ModelAndView;
 24 import com.google.gson.Gson;
 25 import com.svse.entity.Users;
 26 import com.svse.service.ConsumerService;
 27 import com.svse.service.ProducerService;
 28 
 29 @Controller
 30 public class DemoController {
 35     
 36      //队列名Jaycekon (ActiveMQ中设置的队列的名称)
 37     @Resource(name="demoQueueDestination")
 38     private Destination demoQueueDestination;
 39 
 40     //队列消息生产者
 41     @Resource(name="producerService")
 42     private ProducerService producer;
 43     
 44    //队列消息消费者
 45     @Resource(name="consumerService")
 46     private ConsumerService consumer;
 47     
 48     /*
 49      * 准备发消息
 50      */
 51     @RequestMapping(value="/producer",method=RequestMethod.GET)
 52     public ModelAndView producer(){
 53         System.out.println("------------go producer");
 54         
 55         Date now = new Date(); 
 56         SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
 57         String time = dateFormat.format( now ); 
 58         System.out.println(time);
 59         
 60         ModelAndView mv = new ModelAndView();
 61         mv.addObject("time", time);
 62         mv.setViewName("producer");        
 63         return mv;
 64     }
 65     
 66     /*
 67      * 发消息
 68      */
 69     @RequestMapping(value="/onsend",method=RequestMethod.POST)
 70     public ModelAndView producer(@RequestParam("message") String message) {
 71         System.out.println("------------send to jms");
 72         ModelAndView mv = new ModelAndView();
 73         for(int i=0;i<5;i++){
 74             try {
 75                 Users users=new Users("10"+(i+1),"赵媛媛"+(i+1),"女","27","影视演员");
 76                 Gson gson=new Gson();
 77                 String sendMessage=gson.toJson(users);
 78                 System.out.println("发送的消息sendMessage:"+sendMessage.toString());
 79              // producer.sendMessage(demoQueueDestination,sendMessage.toString());//以文本的形式
 80               producer.sendMessageNew(demoQueueDestination, users);//以对象的方式
 81              
 82             } catch (Exception e) {
 83                 e.printStackTrace();
 84             }
 85         }
 86         mv.setViewName("index");
 87         return mv;
 88     }
 89     /*
 90      * 手动接收消息
 91      */
 92     @RequestMapping(value="/receive",method=RequestMethod.GET)
 93     public ModelAndView queue_receive() throws JMSException {
 94         System.out.println("------------receive message");
 95         ModelAndView mv = new ModelAndView();
 96         
 97       //TextMessage tm = consumer.receive(demoQueueDestination);//接收文本消息
 98         
 99         ObjectMessage objMsg=consumer.receiveNew(demoQueueDestination);//接收对象消息
100         Users users= (Users) objMsg.getObject();
101         //mv.addObject("textMessage", tm.getText());
102         mv.addObject("textMessage", users.getUserId()+" || "+users.getUserName());
103         mv.setViewName("receive");
104         return mv;
105     }
106     
107     /*
108      * ActiveMQ Manager Test
109      */
110     @RequestMapping(value="/jms",method=RequestMethod.GET)
111     public ModelAndView jmsManager() throws IOException {
112         System.out.println("------------jms manager");
113         ModelAndView mv = new ModelAndView();
114         mv.setViewName("index");
115         
116         JMXServiceURL url = new JMXServiceURL("");
117         JMXConnector connector = JMXConnectorFactory.connect(url);
118         connector.connect();
119         MBeanServerConnection connection = connector.getMBeanServerConnection();
120         
121         return mv;
122     }
123     
124 }

 

三、对象转换器MessageConverter和消息***MessageListener

在上边的ProducerService和ConsumerService中,不论是发送消息还是接收消息,都可以以文本TextMessage的方式和ObjectMessage的方式.如果是简单的文本消息可以以TextMessage,但是如果需要发送的内容比较多,结构比较复杂,这时候就建议用对象文本ObjectMessage的方式向队列queue中发送消息了.但是这时候就需要用到对象消息转换器MessageConverter.

3.1  消息转换器MessageageConverte

MessageConverter的作用主要有两方面,一方面它可以把我们的非标准化Message对象转换成我们的目标Message对象,这主要是用在发送消息的时候;另一方面它又可以把我们的Message对象 转换成对应的目标对象,这主要是用在接收消息的时候。

 1 package com.svse.util;
 2 
 3 import java.io.Serializable;
 4 
 5 import javax.jms.JMSException;
 6 import javax.jms.Message;
 7 import javax.jms.ObjectMessage;
 8 import javax.jms.Session;
 9 
10 import org.springframework.jms.support.converter.MessageConversionException;
11 import org.springframework.jms.support.converter.MessageConverter;
12 
13 /**
14  *功能说明:通用的消息对象转换类
15  *@author:zsq
16  *create date:2019年7月12日 上午9:28:31
17  *修改人   修改时间  修改描述
18  *Copyright (c)2019北京智华天成科技有限公司-版权所有
19  */
20 public class ObjectMessageConverter implements MessageConverter {
21 
22     
23     //把一个Java对象转换成对应的JMS Message (生产消息的时候)
24     public Message toMessage(Object object, Session session)
25             throws JMSException, MessageConversionException {
26         
27         return session.createObjectMessage((Serializable) object);  
28     }
29 
30     //把一个JMS Message转换成对应的Java对象 (消费消息的时候)
31     public Object fromMessage(Message message) throws JMSException,
32             MessageConversionException {
33         ObjectMessage objMessage = (ObjectMessage) message;  
34         return objMessage.getObject();  
35     }
36 
37 }
注意:写了消息转化器之后还需要的ActiveMQ.xml中进行配置

3.2  消息***MessageageListe

MessageageListe作用就是动态的自行监听消息队列的生产者发送的消息,不需要人工手动接收!

 1 package com.svse.util;
 2 import javax.jms.JMSException;
 3 import javax.jms.Message;
 4 import javax.jms.MessageListener;
 5 import javax.jms.ObjectMessage;
 6 import javax.jms.TextMessage;
 7 
 8 import com.svse.entity.Users;
 9 
10 
11 public class QueueMessageListener implements MessageListener {
12 
13    //添加了***,只要生产者发布了消息,***监听到有消息消费者就会自动消费(获取消息)
14     public void onMessage(Message message) {
15          //(第1种方式)没加转换器之前接收到的是文本消息
16         //TextMessage tm = (TextMessage) message;
17         
18         //(第2种方式)加了转换器之后接收到的ObjectMessage对象消息
19         ObjectMessage objMsg=(ObjectMessage) message;
20          Users users;
21         try {
22             users = (Users) objMsg.getObject();
23             //System.out.println("QueueMessageListener监听到了文本消息:\t" + tm.getText());
24             System.out.println("QueueMessageListener监听到了文本消息:\t" + users);      
25             //do something ...
26         } catch (JMSException e1) {
27             // TODO Auto-generated catch block
28             e1.printStackTrace();
29         }
30     }
31     
32 }
同样写好***后也是需在ActiveMQ.xml中进行配置注册的

四、总结

(1)注册JmsTemplate时,pubSubDomain这个属性的值要特别注意。默认值是false,也就是说默认只是支持queue模式,不支持topic模式。但是,如果将它改为true,则不支持queue模式。因此如果项目需要同时支持queue和topic模式,那么需要注册2个JmsTemplate,同时监听容器也需要注册2个

(2)使用Queue时,生产者只要将Message发送到MQ服务器端,消费者就可以进行消费,而无需生产者程序一直运行;

(3)消息是按照先入先出的顺序,一旦有消费者将Message消费,该Message就会从MQ服务器队列中删去;

(4)有文章说,“生产者”<-->"消费者"是一对一的关系,其实并不准确,从应用中可以看出,一个生产者产生的消息,可以被多个消费者进行消费,只不过多个消费者在消费消息时是竞争的关系,先得到的先消费,一旦消费完成,该消息就会出队列, 就不能被其他消费者再消费了,即“一次性消费”。就是我们熟悉的“点对点”通信了;