ActiveMQ的使用筆記（基本實現原理）

具體原理不進行深入，會用就好。

第一：當然是先安裝ActiveMQ，選擇操作系統位數，安裝成功以后，輸入網址http://ip:8161/admin/，會出現相關頁面，賬號密碼都是admin。在這個頁面上可以看到消息隊列的信息。consume和send使用較多。

 

第二：創建produce和consume。

　　基本的原理都是一樣的，JMS(java message send)的13個規范之一，消息中間件的一些組件拼接連通就行了。具體參考代碼注釋。

容易出錯的地方是消息的格式。

這里有點對點模式和發布/訂閱模式。我使用的時候是在初始化ContextListener的時候初始化ActiveMQ，然后並重載了onMessage事件（MessageConsumer里面定義了一些接口，可以去使用），這樣就不需要一直主動去詢問提供者了，隊列中有消息時會自動觸發該事件。

 

 

參考代碼：

package com.enjoyor.soa.traffic.server.nmim.listener;

import javax.jms.Message;
import javax.jms.MessageListener;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

import com.enjoyor.soa.traffic.server.nmim.util.ActiveMQUtil;
import com.enjoyor.soa.traffic.server.nmim.util.Constants;
import com.enjoyor.soa.traffic.server.nmim.util.InitConfig;
import com.enjoyor.soa.traffic.server.nmim.service.inner.MqManageService;
import com.enjoyor.soa.traffic.util.frame.spring.SpringContextUtil;
import com.enjoyor.soa.traffic.util.helper.LoggerHelper;
import com.enjoyor.soa.traffic.util.pojo.ResultPojo;

/**   
 *    
 * ContextListener   
 * 2016-11-25
 *    
 */
public class ContextListener implements ServletContextListener 
{
    public void contextDestroyed(ServletContextEvent arg0)
    {
        System.out.print("contextDestroyed"); 
    }

    MqManageService manageService;
    
    public void contextInitialized(ServletContextEvent arg0)
    {      
        System.out.print("contextInitialized");  
        String MQNAME = "";
        InitConfig initConfig = new InitConfig();
        initConfig.init();
        MQNAME = InitConfig.confCache.get(Constants.MQNAME).toString();
        ActiveMQUtil.getInstance().receive("queue://" + MQNAME, new MessageListener() {
            @Override
            public void onMessage(Message msg) {
                try {
                    if(null==manageService){
                        manageService = (MqManageService) SpringContextUtil.getBean("mqManageService");
                        manageService.setListDic();
                    }
                    //MqManageService manageService = (MqManageService) SpringContextUtil.getBean("mqManageService");
                    ResultPojo pojo = manageService.getMqMsg(msg);
                    if(!pojo.getappCode().equals("0")){
                        LoggerHelper.LOG.error("接收失敗"+pojo.getResultList());
                    }
                } catch (Exception e) {
                    LoggerHelper.LOG.error(e);
                }
                
            }
        });
    }
    
}



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
package com.enjoyor.soa.traffic.server.nmim.util;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.Session;
import javax.jms.TextMessage;

import org.apache.activemq.command.ActiveMQQueue;
import org.apache.activemq.command.ActiveMQTopic;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jms.core.JmsTemplate;
import org.springframework.jms.core.MessageCreator;

public class ActiveMQUtil {
    
    private ActiveMQUtil(){
        
    }
    private JmsTemplate jmsTemplate;
    public JmsTemplate getJmsTemplate() {
        return jmsTemplate;
    }
    public void setJmsTemplate(JmsTemplate jmsTemplate) {
        this.jmsTemplate = jmsTemplate;
    }
    

    private static ActiveMQUtil mq;
    public static ActiveMQUtil getInstance(){
        if(mq==null){
            ApplicationContext context = new ClassPathXmlApplicationContext("activemq.xml");
            mq=(ActiveMQUtil)context.getBean("activeMQUtil");
        }
        return mq;
    }
    
    
    public Destination getDestination(String name){
        Destination dest=null;
        boolean pubSubDomain=name.toLowerCase().indexOf("topic://")==0;
        String destName = name.replaceFirst("(?i)(topic|queue)://", "");
        if(pubSubDomain){
            dest= new ActiveMQTopic(destName);
        }else{
            dest= new ActiveMQQueue(destName);
        }
        return dest;
    }
    
    public String receive(Destination dest) {
        try {
            TextMessage txtmsg = (TextMessage) getInstance().getJmsTemplate().receive(dest);
            if(null!=txtmsg)return txtmsg.getText();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
    public String receive(String name) {
        return receive(getDestination(name));
    }
    public Connection receive(Destination dest,MessageListener listener){
        try{
            ConnectionFactory factory = getInstance().getJmsTemplate().getConnectionFactory();
            Connection connection = factory.createConnection();
            connection.start();
               
            final Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            MessageConsumer consumer = session.createConsumer(dest);
            consumer.setMessageListener(listener);
            return connection;
        } catch (JMSException e) { }
        return null;
    }
    public Connection receive(String name,MessageListener listener){
        return receive(getDestination(name),listener);
    }
    
    public void send(Destination dest,final String msg){
        try {
            jmsTemplate.send(dest,new MessageCreator() {
                public Message createMessage(Session session) throws JMSException {
                    TextMessage message = session.createTextMessage(msg);
                    return message;
                }
            });
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public void send(String name,final String msg){
        send(getDestination(name),msg);
    }
    
}

注意將ContextListener初始化時注入spring容器中。任何類都需要一個入口，只有進入spring容器中，在jvm中被調用，才有存在的價值。