五、ActiveMQ的Broker(嵌入到java程序)

ActiveMQ的Broker

• 一、是什么
• 二、Java应用嵌入ActiveMQ

一、是什么

• Broker相当于一个ActiveMQ服务器实例
• 实现了用代码的形式启动ActiveMQ将MQ嵌入到Java代码中，以便随时用随时启动，在用的时候再去启动这样能节省了资源，也保证了可用性。
• 用ActiveMQ Broker作为独立的消息服务器来构建Java应用。ActiveMQ也支持在vm中通信基于嵌入的broker，能够无缝的集成其他java应用。

二、Java应用嵌入ActiveMQ

• 工作中还是以单独部署的ActiveMQ使用为主。

1.pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.qingsi.activemq</groupId>
    <artifactId>activemq_test</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <!-- activemq所需要的jar包配置 -->
            <groupId>org.apache.activemq</groupId>
            <artifactId>activemq-all</artifactId>
            <version>5.15.11</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.10.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.apache.xbean/xbean-spring -->
        <dependency>
            <groupId>org.apache.xbean</groupId>
            <artifactId>xbean-spring</artifactId>
            <version>4.15</version>
        </dependency>
        <!--  下面是junit/logback等基础配置  -->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.18</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>

</project>

2.borker实现

package com.qingsi.activemq.Embed;

import org.apache.activemq.broker.BrokerService;

public class EmbedBroker {
    public static void main(String[] args) throws Exception {
        // ActiveMQ也支持在vm中通信基于嵌入的broker
        BrokerService brokerService = new BrokerService();
        brokerService.setUseJmx(true);
        brokerService.addConnector("tcp://localhost:61616");
        brokerService.start();
    }
}

• 运行后，启动一个mini版的AcitveMQ
  

3.生产者

package com.qingsi.activemq;

import org.apache.activemq.ActiveMQConnectionFactory;

import javax.jms.*;

public class JmsProduce {

    public static final String ACTIVEMQ_URL = "tcp://localhost:61616";
    public static final String QUEUE_NAME = "queue01";

    public static void main(String[] args) throws JMSException {
        //1.创建连接工厂，按照给定的URL，采用默认的用户名密码
        ActiveMQConnectionFactory activeMQConnectionFactory = new ActiveMQConnectionFactory(ACTIVEMQ_URL);
        //2.通过连接工厂,获得connection并启动访问
        Connection connection = activeMQConnectionFactory.createConnection();
        connection.start();
        //3.创建会话session
        //两个参数transacted=事务,acknowledgeMode=确认模式(签收)
        //开启事务需要commit
        Session session = connection.createSession(true, Session.AUTO_ACKNOWLEDGE);
        //4.创建目的地(具体是队列queue还是主题topic)
        Queue queue = session.createQueue(QUEUE_NAME);
        //5.创建消息的生产者,并设置不持久化消息
        MessageProducer producer = session.createProducer(queue);
        //6.通过使用消息生产者,生产三条消息,发送到MQ的队列里面
        try {
            for (int i = 0; i < 3; i++) {
                TextMessage textMessage = session.createTextMessage("tx msg--" + i);
                producer.send(textMessage);
            }
            //7.提交事务
            session.commit();
            System.out.println("消息发送完成");
        } catch (Exception e) {
            System.out.println("出现异常,消息回滚");
            session.rollback();
        } finally {
            //8.关闭资源
            producer.close();
            session.close();
            connection.close();
        }

    }

}

4.消费者

package com.qingsi.activemq;

import org.apache.activemq.ActiveMQConnectionFactory;

import javax.jms.*;
import java.io.IOException;

public class JmsConsumer {
    public static final String ACTIVEMQ_URL = "tcp://localhost:61616";
    public static final String QUEUE_NAME = "queue01";

    public static void main(String[] args) throws JMSException, IOException {
        //1.创建连接工厂，按照给定的URL，采用默认的用户名密码
        ActiveMQConnectionFactory activeMQConnectionFactory = new ActiveMQConnectionFactory(ACTIVEMQ_URL);
        //2.通过连接工厂,获得connection并启动访问
        Connection connection = activeMQConnectionFactory.createConnection();
        connection.start();
        //3.创建会话session
        //两个参数transacted=事务,acknowledgeMode=确认模式(签收)
        //消费者开启了事务就必须手动提交，不然会重复消费消息
        Session session = connection.createSession(false, Session.CLIENT_ACKNOWLEDGE);
        //4.创建目的地(具体是队列queue还是主题topic)
        Queue queue = session.createQueue(QUEUE_NAME);
        //5.创建消息的消费者,指定消费哪一个队列里面的消息
        MessageConsumer messageConsumer = session.createConsumer(queue);
        //6.通过监听的方式消费消息
        messageConsumer.setMessageListener(new MessageListener() {
            @Override
            public void onMessage(Message message) {
                if (message instanceof TextMessage) {
                    try {

                        TextMessage textMessage = (TextMessage) message;
                        System.out.println("***消费者接收broker的消息:   " + textMessage.getText());
                        // 手动签收
                        textMessage.acknowledge();
                    } catch (Exception e) {
                        System.out.println("出现异常，消费失败，放弃消费");
                    }
                }
            }
        });
        //7.关闭资源
        System.in.read();
        messageConsumer.close();
        session.close();
        connection.close();
    }
}