Java SDK接入示例_使用AMQP服务端订阅_服务端订阅_消息通信

本文介绍使用AMQP协议的JMS客户端接入阿里云物联网平台，接收服务端订阅消息的示例。

开发环境

本示例使用的开发环境为JDK 1.7及以上版本。

下载SDK

AMQP SDK为开源SDK。如果您使用Java开发语言，推荐使用Apache Qpid JMS客户端。请访问Qpid JMS 0.47.0下载客户端和查看使用说明。

添加Maven依赖

<!-- amqp 1.0 qpid client -->
 <dependency>
   <groupId>org.apache.qpid</groupId>
   <artifactId>qpid-jms-client</artifactId>
   <version>0.47.0</version>
 </dependency>
 <!-- util for base64-->
 <dependency>
   <groupId>commons-codec</groupId>
  <artifactId>commons-codec</artifactId>
  <version>1.10</version>
</dependency>

代码示例

以下Demo中涉及的参数说明，请参见AMQP客户端接入说明。

import java.net.URI;
import java.util.Hashtable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.MessageProducer;
import javax.jms.Session;
import javax.naming.Context;
import javax.naming.InitialContext;
import org.apache.commons.codec.binary.Base64;
import org.apache.qpid.jms.JmsConnection;
import org.apache.qpid.jms.JmsConnectionListener;
import org.apache.qpid.jms.message.JmsInboundMessageDispatch;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class AmqpJavaClientDemo {

    private final static Logger logger = LoggerFactory.getLogger(AmqpJavaClientDemo.class);

    //业务处理异步线程池，线程池参数可以根据您的业务特点调整；或者您也可以用其他异步方式处理接收到的消息
    private final static ExecutorService executorService = new ThreadPoolExecutor(
        Runtime.getRuntime().availableProcessors(),
        Runtime.getRuntime().availableProcessors() * 2, 60, TimeUnit.SECONDS,
        new LinkedBlockingQueue<>(50000));

    public static void main(String[] args) throws Exception {
        //参数说明，请参见上一篇文档：AMQP客户端接入说明。
        String accessKey = "${YourAccessKey}";
        String accessSecret = "${YourAccessSecret}";
        String consumerGroupId = "${YourConsumerGroupId}";
        long timeStamp = System.currentTimeMillis();
        //签名方法：支持hmacmd5，hmacsha1和hmacsha256
        String signMethod = "hmacsha1";
        //控制台服务端订阅中消费组状态页客户端ID一栏将显示clientId参数。
        //建议使用机器UUID、MAC地址、IP等唯一标识等作为clientId。便于您区分识别不同的客户端。
        String clientId = "${YourClientId}";

        //UserName组装方法，请参见上一篇文档：AMQP客户端接入说明。
        String userName = clientId + "|authMode=aksign"
            + ",signMethod=" + signMethod
            + ",timestamp=" + timeStamp
            + ",authId=" + accessKey
            + ",consumerGroupId=" + consumerGroupId
            + "|";
        //password组装方法，请参见上一篇文档：AMQP客户端接入说明。
        String signContent = "authId=" + accessKey + "&timestamp=" + timeStamp;
        String password = doSign(signContent,accessSecret, signMethod);
        //按照qpid-jms的规范，组装连接URL。
        String connectionUrl = "failover:(amqps://${uid}.iot-amqp.${regionId}.aliyuncs.com:5671?amqp.idleTimeout=80000)"
            + "?failover.reconnectDelay=30";

        Hashtable<String, String> hashtable = new Hashtable<>();
        hashtable.put("connectionfactory.SBCF",connectionUrl);
        hashtable.put("queue.QUEUE", "default");
        hashtable.put(Context.INITIAL_CONTEXT_FACTORY, "org.apache.qpid.jms.jndi.JmsInitialContextFactory");
        Context context = new InitialContext(hashtable);
        ConnectionFactory cf = (ConnectionFactory)context.lookup("SBCF");
        Destination queue = (Destination)context.lookup("QUEUE");
        // Create Connection
        Connection connection = cf.createConnection(userName, password);
        ((JmsConnection) connection).addConnectionListener(myJmsConnectionListener);
        // Create Session
        // Session.CLIENT_ACKNOWLEDGE: 收到消息后，需要手动调用message.acknowledge()
        // Session.AUTO_ACKNOWLEDGE: SDK自动ACK（推荐）
        Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
        connection.start();
        // Create Receiver Link
        MessageConsumer consumer = session.createConsumer(queue);
        consumer.setMessageListener(messageListener);
    }

    private static MessageListener messageListener = new MessageListener() {
        @Override
        public void onMessage(Message message) {
            try {
                //1.收到消息之后一定要ACK
                // 推荐做法：创建Session选择Session.AUTO_ACKNOWLEDGE，这里会自动ACK。
                // 其他做法：创建Session选择Session.CLIENT_ACKNOWLEDGE，这里一定要调message.acknowledge()来ACK。
                // message.acknowledge();
                //2.建议异步处理收到的消息，确保onMessage函数里没有耗时逻辑。
                // 如果业务处理耗时过程过长阻塞住线程，可能会影响SDK收到消息后的正常回调。
                executorService.submit(() -> processMessage(message));
            } catch (Exception e) {
                logger.error("submit task occurs exception ", e);
            }
        }
    };

    /**
     * 在这里处理您收到消息后的具体业务逻辑。
     */
    private static void processMessage(Message message) {
        try {
            byte[] body = message.getBody(byte[].class);
            String content = new String(body);
            String topic = message.getStringProperty("topic");
            String messageId = message.getStringProperty("messageId");
            logger.info("receive message"
                + ", topic = " + topic
                + ", messageId = " + messageId
                + ", content = " + content);
        } catch (Exception e) {
            logger.error("processMessage occurs error ", e);
        }
    }

    private static JmsConnectionListener myJmsConnectionListener = new JmsConnectionListener() {
        /**
         * 连接成功建立
         */
        @Override
        public void onConnectionEstablished(URI remoteURI) {
            logger.info("onConnectionEstablished, remoteUri:{}", remoteURI);
        }

        /**
         * 尝试过最大重试次数之后，最终连接失败。
         */
        @Override
        public void onConnectionFailure(Throwable error) {
            logger.error("onConnectionFailure, {}", error.getMessage());
        }

        /**
         * 连接中断。
         */
        @Override
        public void onConnectionInterrupted(URI remoteURI) {
            logger.info("onConnectionInterrupted, remoteUri:{}", remoteURI);
        }

        /**
         * 连接中断后又自动重连上。
         */
        @Override
        public void onConnectionRestored(URI remoteURI) {
            logger.info("onConnectionRestored, remoteUri:{}", remoteURI);
        }

        @Override
        public void onInboundMessage(JmsInboundMessageDispatch envelope) {}

        @Override
        public void onSessionClosed(Session session, Throwable cause) {}

        @Override
        public void onConsumerClosed(MessageConsumer consumer, Throwable cause) {}

        @Override
        public void onProducerClosed(MessageProducer producer, Throwable cause) {}
    };

    /**
     * password签名计算方法，请参见上一篇文档：AMQP客户端接入说明。
     */
    private static String doSign(String toSignString, String secret, String signMethod) throws Exception {
        SecretKeySpec signingKey = new SecretKeySpec(secret.getBytes(), signMethod);
        Mac mac = Mac.getInstance(signMethod);
        mac.init(signingKey);
        byte[] rawHmac = mac.doFinal(toSignString.getBytes());
        return Base64.encodeBase64String(rawHmac);
    }
}