Jms基礎知識整理

nbtymm 2007-03-23

展開全文

開始文章之前先澄清幾個概念

什么是消息
消息是一個用于在組件和應用程序之間通訊的的方法。消息之間的傳遞是點對點的。任何終端之間都可以相互接受和發(fā)送消息。并且每個終端都必須遵守如下的規(guī)則
-> 創(chuàng)建消息 -> 發(fā)送消息 -> 接收消息 -> 讀取消息

為什么要使用消息
理由很簡單，消息是一個分布式的低耦合通訊方案。A發(fā)送一個消息到一個agent ,B作為接受者去agent上獲取消息。但是A,B不需要同時到agent上去注冊。agent作為一個中轉為A,B提供搞效率的通訊服務。

開發(fā)者的關注點
走到這里，我也不想去解釋jms spec上那些抽象且復雜的概念了，說的很白，1年多了我自己也沒弄懂是個什么東西，也沒時間從頭到尾去仔細的看，同時我認為沒必要，我所關注的是如何讓jms跑起來，并且工作正常，所以spec只是個字典，當我需要用的時候才去查。

開發(fā)者的jms環(huán)境
遵守簡單明了的原則，所謂jms環(huán)境只是2個對象
1> ConnectionFactory
2> Destination
通常Provider會提供JNDI的對象獲取，具體方法可以去Privider的網站上搜索jndi support

下面我以jbossMq為介質跑一個簡單的jms，為了保證jms的本質清晰，我沒有使用jbossMq的Api，而是直接調用的jms Api.

java 代碼

package com.javaeye.jms.jboss;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.MessageConsumer;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.QueueSender;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public class JbossNativeJmsImpl {
/**
* @author zuly
*
* following jms ptp domain, use an simple text message to test
*
* A jms ptp sender will following the steps below!
* 1> get an ConnectionFactory use JNDI Lookup Or Initial it yourself
* 2> use this ConnectionFactory to start a jms connection
* [spec to jms 1.1 apito get the main idea of it ]
* 3> use connection to create a jms session
* 4> get a queue destination / messege agent
* 5> start the Producer[jms1.1 spec] by a session
* 6> get messege Object or initial it yourself by implements the messegeor
* it‘s sub interfaces
* 7> call sender or send it selfing
* 8> finallized the connection object or it will throw a warning to you!
*
* @param messege
* @throws NamingException
* @throws JMSException
*/
public void sendingProcessing(String messege) throws NamingException, JMSException{
Context ctx = new InitialContext();
ConnectionFactory cf = (ConnectionFactory) ctx.lookup("java:JmsXA");
Connection conn = cf.createConnection();
Session session = conn.createSession(false, Session.AUTO_ACKNOWLEDGE);
Destination dest = (Queue) ctx.lookup("queue/A");
MessageProducer msgp = session.createProducer(dest);
QueueSender sender = (QueueSender) msgp;
TextMessage msg = session.createTextMessage();
msg.setText(messege);
sender.send(msg);
conn.close();
}
/**
* @author zuly
*
* following jms ptp domain, use an simple text message to test
*
* A jms ptp retriver will following the steps below!
* 1> get an ConnectionFactory use JNDI Lookup Or Initial it yourself
* 2> use this ConnectionFactory to start a jms connection
* [spec to jms 1.1 api to get the main idea of it ]
* 3> use connection to create a jms session
* 4> get a queue destination / messege agent
* 5> retrive a consumer from session
* 6> start the jms connection to retrivte the message
* 7> get message from consumer
*
* @return textMessege
* @throws NamingException
* @throws JMSException
*/
public String retriveingProcessing() throws NamingException, JMSException{
Context ctx = new InitialContext();
ConnectionFactory cf = (ConnectionFactory) ctx.lookup("java:JmsXA");
Connection conn = cf.createConnection();
Session session = conn.createSession(false, Session.AUTO_ACKNOWLEDGE);
Destination dest = (Queue) ctx.lookup("queue/A");
MessageConsumer msgconsumer = session.createConsumer(dest);
//MessageListener ml = new JmsListenner();
//msgconsumer.setMessageListener(ml);
conn.start();
TextMessage msg = (TextMessage) msgconsumer.receive();
conn.close();
System.out.println("messege is" + msg.getText());
return msg.getText();
}
}

注意retrive函數中comment的掉的兩行，消息Listener的作用是實現異步通訊，但是它有一個約定，必須和發(fā)送者
保持物理上的分離，針對于jboss而言，就要求這個Listener必須跑在容器外面。這是一個很搞的問題，每天Jms的郵件列表里面都有無數的這樣的問題發(fā)過來。但是回復的人很少。我自己也從來不回復。其實我也不清楚寫這篇文章到底是出于什么目的，怕只是讓這么一個簡單的問題有一個回答而已。

把下面這個程序跑起來就可以異步接受消息了。

java 代碼

package com.javaeye.jms.jboss;
import java.util.Properties;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.Session;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import com.javaeye.spring.services.jms.mdp.JmsListenner;
public class JbossJmsAsync {
/**
* @param args
* @throws NamingException
* @throws JMSException
*/
public static void main(String[] args) throws NamingException, JMSException {
Properties pops = new Properties();
pops.setProperty("jboss.bind.address", "0.0.0.0");
pops.setProperty("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");
pops.setProperty("java.naming.factory.url.pkgs", "org.jboss.naming:org.jnp.interfaces");
pops.setProperty("java.naming.provider.url", "localhost");
Context ctx = new InitialContext(pops);
ConnectionFactory cf = (ConnectionFactory) ctx.lookup("ConnectionFactory");
Connection conn = cf.createConnection();
Session session = conn.createSession(false, Session.AUTO_ACKNOWLEDGE);
Destination dest = (Destination) ctx.lookup("queue/A");
MessageConsumer msgConsumer = session.createConsumer(dest);
MessageListener ml = new JmsListenner();
msgConsumer.setMessageListener(ml);
conn.start();
}
}

javaeye的主題好像是spring，為了迎合領導，下面我把這套東西跑在spring里面。同時我發(fā)現spring對jms的包裝真的簡單，而且還提供了一個模版，雖然這個模版的接口是在是很羅唆。

ps:今天是第1次用spring在reference里找了半天找不到方法注入的辦法，于是google了一個注入辦法，不合理的地方請大家指出。首先我通過方法來注入ConnectionFactory和Destination這兩個對象來支撐jms環(huán)境

java 代碼

package com.javaeye.spring.services.jms.mdp;
import java.util.Properties;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.Queue;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public class UserJmsTransactionUtil {
private String connectionFactoryJndiLookUp;
private String destinationJndiLookUp;
private String localConnectionFactoryJndiLookUp;
private String containerType;
public String getConnectionFactoryJndiLookUp() {
return connectionFactoryJndiLookUp;
}
public void setConnectionFactoryJndiLookUp(String connectionFactoryJndiLookUp) {
this.connectionFactoryJndiLookUp = connectionFactoryJndiLookUp;
}
public String getDestinationJndiLookUp() {
return destinationJndiLookUp;
}
public void setDestinationJndiLookUp(String destinationJndiLookUp) {
this.destinationJndiLookUp = destinationJndiLookUp;
}
public ConnectionFactory getConnectionFactory() throws NamingException{
Context ctx = new InitialContext();
ConnectionFactory cf = (ConnectionFactory) ctx.lookup(connectionFactoryJndiLookUp);
return cf;
}
public Destination getJmsDestination() throws NamingException{
Context ctx = new InitialContext();
Destination dest = (Queue) ctx.lookup(destinationJndiLookUp);
return dest;
}
public ConnectionFactory getQueueConnectionFactory() throws NamingException{
Properties pops = new Properties();
pops.setProperty("jboss.bind.address", "0.0.0.0");
pops.setProperty("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");
pops.setProperty("java.naming.factory.url.pkgs", "org.jboss.naming:org.jnp.interfaces");
pops.setProperty("java.naming.provider.url", "localhost");
Context ctx = new InitialContext(pops);
ConnectionFactory cf = (ConnectionFactory) ctx.lookup(localConnectionFactoryJndiLookUp);
return cf;
}
public Destination getLocalJmsDestination() throws NamingException{
Properties pops = new Properties();
pops.setProperty("jboss.bind.address", "0.0.0.0");
pops.setProperty("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");
pops.setProperty("java.naming.factory.url.pkgs", "org.jboss.naming:org.jnp.interfaces");
pops.setProperty("java.naming.provider.url", "localhost");
Context ctx = new InitialContext(pops);
Destination dest = (Destination) ctx.lookup(destinationJndiLookUp);
return dest;
}
public String getLocalConnectionFactoryJndiLookUp() {
return localConnectionFactoryJndiLookUp;
}
public void setLocalConnectionFactoryJndiLookUp(
String localConnectionFactoryJndiLookUp) {
this.localConnectionFactoryJndiLookUp = localConnectionFactoryJndiLookUp;
}
}

發(fā)送端的配置如下

xml 代碼

<beans>
<bean id="userJmsUtil" class="com.javaeye.spring.services.jms.mdp.UserJmsTransactionUtil">
<property name="connectionFactoryJndiLookUp" value="java:JmsXA">property>
<property name="destinationJndiLookUp" value="queue/A">property>
<property name="localConnectionFactoryJndiLookUp" value="ConnectionFactory">property>
bean>
<bean id="connectionFactory" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<property name="targetObject" ref="userJmsUtil">property>
<property name="targetMethod" value="getConnectionFactory">property>
bean>
<bean id="queue" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<property name="targetObject" ref="userJmsUtil">property>
<property name="targetMethod" value="getJmsDestination">property>
bean>
<bean id="jmsQueue" class="org.springframework.jms.core.JmsTemplate">
<property name="connectionFactory" ref="connectionFactory">property>
<property name="defaultDestination" ref="queue">property>
<property name="messageConverter">
<bean class="org.springframework.jms.support.converter.SimpleMessageConverter">bean>
property>
bean>
beans>

ps:javaeye的模版工具bug還真多,不管了.

如果使用Listenner的化,一樣需要遵守發(fā)送者和接收者物理隔離的原則,我的做法是把發(fā)送者配到一個xml中,在把接受者配到另外一個xml中去,發(fā)送的配置綁定到容器里,接收者的跑在本地.否則spring初始化是過不去的.

下面這個程序是發(fā)送消息的程序.使用了spring的模版,發(fā)條消息比new個對象還簡單.同時spring還提供了適配器的接口,一樣通過聲明式的配置,這樣可以在同一個接口里發(fā)送各種類型的消息了.同時支持事務,我還不知道這個有什么用呵呵,第1次使用嘛!但是就使用上來說,spring是最簡單的.2者都只需要注入一個對象而已.

java 代碼

@Test public void send(){
ApplicationContext ac = new FileSystemXmlApplicationContext("jms.xml");
BeanFactory bf = ac;
JmsTemplate jt = (JmsTemplate) bf.getBean("jmsQueue");
jt.convertAndSend("2132134");
}

接收端的配置如下

xml 代碼

xml version="1.0" encoding="UTF-8"?>
>
<beans>
<bean id="listenner" class="com.javaeye.spring.services.jms.mdp.JmsListenner">bean>
<bean id="userJmsUtil" class="com.javaeye.spring.services.jms.mdp.UserJmsTransactionUtil">
<property name="connectionFactoryJndiLookUp" value="java:JmsXA">property>
<property name="destinationJndiLookUp" value="queue/A">property>
<property name="localConnectionFactoryJndiLookUp" value="ConnectionFactory">property>
bean>
<bean id="localConnectionFactory" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<property name="targetObject" ref="userJmsUtil">property>
<property name="targetMethod" value="getQueueConnectionFactory">property>
bean>
<bean id="localDestination" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<property name="targetObject" ref="userJmsUtil">property>
<property name="targetMethod" value="getLocalJmsDestination">property>
bean>
<bean id="listenerContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
<property name="concurrentConsumers" value="5">property>
<property name="connectionFactory" ref="localConnectionFactory">property>
<property name="destination" ref="localDestination">property>
<property name="messageListener" ref="listenner">property>
bean>
beans>

接收端由于需要從jbossmq里取ConnectionFactory和Destination,所以,我調用的是userJmsUtil的localLookup.這個函數的作用等同于發(fā)送者的那個函數,只不過前者是容器外獲取,而后者是容器內的而已.

java 代碼

package com.javaeye.spring.services.jms.mdp;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;
public class JmsListenner implements MessageListener {
public void onMessage(Message message) {
try {
TextMessage msg = (TextMessage) message;
System.out.println(msg.getText());
} catch (JMSException e) { e.printStackTrace(); }
}
}

spring對jms的整合里提到了一個jms provider ActiveMQ,要用一個開源框架要做的第一件事就是先跑一個demo起來,同樣,我們要做的事還是獲取ConnectionFactory和Destination對象,還好,ActiveMQ的JNDI實現比jbossMQ還要簡單,直接通過一個本地的Context就可以查到了,具體的可以參照ActiveMQ官方的支持文檔.