Spring基於JMS實現遠程訪問

使用JMS作爲底層通信協議，Spring提供了很好的支持。我們可以基於JMS將服務暴露給外部，這一切對於外部完全透明。這裏我們基於開源消息中間件ActiveMQ作爲中間代理，通過在服務端將服務以消息的形式發佈到代理服務器上，然後客戶端通過代理服務器實現對服務的遠程調用。

ActiveMQ的BrokerService可以非常容易地實現服務端與客戶端進行通信的中間代理，Spring配置broker.xml內容如下所示：

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> <bean id="broker" class="org.apache.activemq.broker.BrokerService" /> </beans>

通過Spring的IOC容器來管理BrokerService。實現一個基於ActiveMQ的消息代理服務，如下所示：

package org.shirdrn.spring.remote.jms; import org.apache.activemq.broker.BrokerService; import org.apache.log4j.Logger; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class Broker { private static final Logger LOG = Logger.getLogger(Broker.class); private static final String CONNECTOR_ADDRESS = "tcp://192.168.1.103:61616"; public static void main(String[] args) { ApplicationContext ctx = new ClassPathXmlApplicationContext( new String[] { "org/shirdrn/spring/remote/jms/broker.xml" }); BrokerService broker = (BrokerService) ctx.getBean("broker"); try { broker.setBrokerName("myBroker"); broker.setUseJmx(true); broker.addConnector(CONNECTOR_ADDRESS); broker.start(); LOG.info("Broker service started."); Object lock = new Object(); synchronized (lock) { lock.wait(); } } catch (InterruptedException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } }

啓動後，代理監聽61616，等待服務端發佈服務，以及遠程客戶端調用服務。

看一下，服務端如何進行實現。

定義服務接口和服務實現。服務接口，代碼如下所示：

package org.shirdrn.spring.remote.jms; public interface AccountService { int queryBalance(String mobileNo); String shoopingPayment(String mobileNo, byte protocol); }

實現上述接口，示例代碼如下所示：

package org.shirdrn.spring.remote.jms; import org.apache.log4j.Logger; public class MobileAccountServiceImpl implements AccountService { private static final Logger LOG = Logger.getLogger(MobileAccountServiceImpl.class); public int queryBalance(String mobileNo) { if (mobileNo != null) return 100; return 0; } public String shoopingPayment(String mobileNo, byte protocol) { StringBuffer sb = new StringBuffer().append("Your mobile number is /"") .append(mobileNo).append("/", protocol type is /"").append( protocol).append("/"."); LOG.info(sb.toString()); return sb.toString(); } }

然後，服務端的配置server.xml，內容如下所示：

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> <bean class="org.springframework.jms.listener.SimpleMessageListenerContainer"> <property name="connectionFactory" ref="connectionFactory" /> <property name="destination" ref="myQueue" /> <property name="concurrentConsumers" value="3" /> <property name="messageListener" ref="myAccountService" /> <property name="taskExecutor" ref="threadPool" /> </bean> <bean id="connectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory"> <property name="brokerURL" value="tcp://192.168.1.103:61616" /> </bean> <bean id="myQueue" class="org.apache.activemq.command.ActiveMQQueue"> <constructor-arg value="shirdrnQ" /> </bean> <bean id="myAccountService" class="org.springframework.jms.remoting.JmsInvokerServiceExporter"> <property name="serviceInterface" value="org.shirdrn.spring.remote.jms.AccountService" /> <property name="service"> <bean class="org.shirdrn.spring.remote.jms.MobileAccountServiceImpl" /> </property> </bean> <bean id="threadPool" class="org.springframework.core.task.SimpleAsyncTaskExecutor"> <property name="daemon" value="true" /> <property name="concurrencyLimit" value="300" /> <property name="threadNamePrefix" value="SERVICE" /> </bean> </beans>

通過Spring的org.springframework.jms.listener.SimpleMessageListenerContainer實現服務的發佈，可以配置的屬性有：

connectionFactory         連接工廠

destination                    消息目的地，基於ActiveMQ則是一個消息隊列

concurrentConsumers   併發消息消費者數量

messageListener           消息監聽器

taskExecutor                 線程池

通過上面配置可以看到，連接工廠指定了代理監聽服務的端口，我們通過服務端發佈服務，作爲消息生產者將服務以消息的形式發佈，然後客戶端作爲服務的消費者，通過代理來實現對遠程發佈服務的調用。

服務端啓動的實現，如下所示：

package org.shirdrn.spring.remote.jms; import org.apache.log4j.Logger; import org.springframework.context.support.ClassPathXmlApplicationContext; public class Server { private static final Logger LOG = Logger.getLogger(Server.class); public static void main(String[] args) throws Exception { new ClassPathXmlApplicationContext( new String[] { "org/shirdrn/spring/remote/jms/server.xml" }); LOG.info("Server started."); } }

再看一下，客戶端如何進行遠程訪問。

對應的客戶端的配置client.xml，內容如下所示：

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> <bean id="connectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory"> <property name="brokerURL" value="tcp://192.168.1.103:61616" /> </bean> <bean id="myQueue" class="org.apache.activemq.command.ActiveMQQueue"> <constructor-arg value="shirdrnQ" /> </bean> <bean id="myAccountService" class="org.springframework.jms.remoting.JmsInvokerProxyFactoryBean"> <property name="serviceInterface" value="org.shirdrn.spring.remote.jms.AccountService" /> <property name="connectionFactory" ref="connectionFactory" /> <property name="queue" ref="myQueue" /> </bean> </beans>

主要是基於Spring提供的org.springframework.jms.remoting.JmsInvokerProxyFactoryBean來實現，通過消息中間件代理，調用遠程發佈的服務。

需要注意的是，客戶端是通過消息隊列（org.apache.activemq.command.ActiveMQQueue）的名稱（如上述爲shirdrnQ）來獲取消息（遠程服務），如果無法識別消息隊列是無法實現服務的遠程訪問的。

客戶端實現遠程訪問，示例代碼如下所示：

package org.shirdrn.spring.remote.jms; import org.apache.log4j.Logger; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class Client { private static final Logger LOG = Logger.getLogger(Client.class); static int index = 0; private static void invoke(AccountService service) { String mobileNo = "1380013800" + (String.valueOf(index++)); String result = service.shoopingPayment(mobileNo, (byte) 3); LOG.info("Client gets result: " + result); } public static void main(String[] args) throws Exception { ApplicationContext ctx = new ClassPathXmlApplicationContext( new String[] { "org/shirdrn/spring/remote/jms/client.xml" }); AccountService service = (AccountService) ctx .getBean("myAccountService"); for(int i=0; i<100; i++) { invoke(service); } } }