MQTT 介绍
- 它是一种 机器之间通讯 machine-to-machine (M2M)、物联网 Internet of Things (IoT)常用的一种轻量级消息传输协议
- 适用于网络带宽较低的场合
- 包含发布、订阅模式,通过一个代理服务器(broker),任何一个客户端(client)都可以订阅或者发布某个主题的消息,然后订阅了该主题的客户端则会收到该消息
mqtt还是之前公司有需求所以写的一个demo,在这里记录下来,方便有人使用的时候查阅,不涉及mqtt的具体讲解,只是贴代码和运行过程。
RaindeMacBook-Pro:bin rain$ ./apollo create mybroker Creating apollo instance at: mybroker Generating ssl keystore... Warning: JKS 密钥库使用专用格式。建议使用 "keytool -importkeystore -srckeystore keystore -destkeystore keystore -deststoretype pkcs12" 迁移到行业标准格式 PKCS12。 You can now start the broker by executing: "/Users/rain/Documents/Soft/apache-apollo-1.7.1/bin/mybroker/bin/apollo-broker" run Or you can run the broker in the background using: "/Users/rain/Documents/Soft/apache-apollo-1.7.1/bin/mybroker/bin/apollo-broker-service" start 复制代码
RaindeMacBook-Pro:bin rain$ ls apollo apollo.cmd mybroker testbroker RaindeMacBook-Pro:bin rain$ cd mybroker/ RaindeMacBook-Pro:mybroker rain$ ls bin data etc log tmp RaindeMacBook-Pro:mybroker rain$ cd bin RaindeMacBook-Pro:bin rain$ ls apollo-broker apollo-broker-service 复制代码
<dependency> <groupId>org.eclipse.paho</groupId> <artifactId>org.eclipse.paho.client.mqttv3</artifactId> <version>1.2.0</version> </dependency> 复制代码
import org.eclipse.paho.client.mqttv3.*; import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence; public class MqttServer2 { /** * 代理服务器ip地址 */ public static final String MQTT_BROKER_HOST = "tcp://127.0.0.1:61613"; /** * 订阅标识 */ public static final String MQTT_TOPIC = "test2"; private static String userName = "admin"; private static String password = "password"; /** * 客户端唯一标识 */ public static final String MQTT_CLIENT_ID = "android_server_xiasuhuei32"; private static MqttTopic topic; private static MqttClient client; public static void main(String... args) { // 推送消息 MqttMessage message = new MqttMessage(); try { client = new MqttClient(MQTT_BROKER_HOST, MQTT_CLIENT_ID, new MemoryPersistence()); MqttConnectOptions options = new MqttConnectOptions(); options.setCleanSession(true); options.setUserName(userName); options.setPassword(password.toCharArray()); options.setConnectionTimeout(10); options.setKeepAliveInterval(20); topic = client.getTopic(MQTT_TOPIC); message.setQos(1); message.setRetained(false); message.setPayload("message from server222222".getBytes()); client.connect(options); while (true) { MqttDeliveryToken token = topic.publish(message); token.waitForCompletion(); System.out.println("已经发送222"); Thread.sleep(10000); } } catch (Exception e) { e.printStackTrace(); } } } 复制代码
import org.eclipse.paho.client.mqttv3.*; import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence; public class MyMqttClient { /** * 代理服务器ip地址 */ public static final String MQTT_BROKER_HOST = "tcp://127.0.0.1:61613"; /** * 客户端唯一标识 */ public static final String MQTT_CLIENT_ID = "android_xiasuhuei321"; /** * 订阅标识 */ // public static final String MQTT_TOPIC = "xiasuhuei321"; /** * */ public static final String USERNAME = "admin"; /** * 密码 */ public static final String PASSWORD = "password"; public static final String TOPIC_FILTER = "test2"; private volatile static MqttClient mqttClient; private static MqttConnectOptions options; public static void main(String... args) { try { // host为主机名,clientid即连接MQTT的客户端ID,一般以客户端唯一标识符表示, // MemoryPersistence设置clientid的保存形式,默认为以内存保存 mqttClient = new MqttClient(MQTT_BROKER_HOST, MQTT_CLIENT_ID, new MemoryPersistence()); // 配置参数信息 options = new MqttConnectOptions(); // 设置是否清空session,这里如果设置为false表示服务器会保留客户端的连接记录, // 这里设置为true表示每次连接到服务器都以新的身份连接 options.setCleanSession(true); // 设置用户名 options.setUserName(USERNAME); // 设置密码 options.setPassword(PASSWORD.toCharArray()); // 设置超时时间 单位为秒 options.setConnectionTimeout(10); // 设置会话心跳时间 单位为秒 服务器会每隔1.5*20秒的时间向客户端发送个消息判断客户端是否在线,但这个方法并没有重连的机制 options.setKeepAliveInterval(20); // 连接 mqttClient.connect(options); // 订阅 mqttClient.subscribe(TOPIC_FILTER); // 设置回调 mqttClient.setCallback(new MqttCallback() { @Override public void connectionLost(Throwable throwable) { System.out.println("connectionLost"); } @Override public void messageArrived(String s, MqttMessage mqttMessage) throws Exception { System.out.println("Topic: " + s + " Message: " + mqttMessage.toString()); } @Override public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) { } }); } catch (Exception e) { e.printStackTrace(); } } } 复制代码
import org.eclipse.paho.client.mqttv3.MqttClient; import org.eclipse.paho.client.mqttv3.MqttConnectOptions; import org.eclipse.paho.client.mqttv3.MqttException; import org.eclipse.paho.client.mqttv3.MqttMessage; import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence; /** *发布端 */ public class PublishSample { public static void main(String[] args) { String topic = "test2"; String content = "hello 哈哈"; int qos = 1; String broker = "tcp://127.0.0.1:61613"; String userName = "admin"; String password = "password"; String clientId = "pubClient"; // 内存存储 MemoryPersistence persistence = new MemoryPersistence(); try { // 创建客户端 MqttClient sampleClient = new MqttClient(broker, clientId, persistence); // 创建链接参数 MqttConnectOptions connOpts = new MqttConnectOptions(); // 在重新启动和重新连接时记住状态 connOpts.setCleanSession(false); // 设置连接的用户名 connOpts.setUserName(userName); connOpts.setPassword(password.toCharArray()); // 建立连接 sampleClient.connect(connOpts); // 创建消息 MqttMessage message = new MqttMessage(content.getBytes()); // 设置消息的服务质量 message.setQos(qos); // 发布消息 sampleClient.publish(topic, message); // 断开连接 sampleClient.disconnect(); // 关闭客户端 sampleClient.close(); } catch (MqttException me) { System.out.println("reason " + me.getReasonCode()); System.out.println("msg " + me.getMessage()); System.out.println("loc " + me.getLocalizedMessage()); System.out.println("cause " + me.getCause()); System.out.println("excep " + me); me.printStackTrace(); } } } 复制代码
import org.eclipse.paho.client.mqttv3.*; import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence; /** *订阅端 */ public class SubscribeSample { public static void main(String[] args) throws MqttException { String HOST = "tcp://127.0.0.1:61613"; String TOPIC = "test2"; int qos = 1; String clientid = "subClient"; String userName = "admin"; String passWord = "password"; try { // host为主机名,test为clientid即连接MQTT的客户端ID,一般以客户端唯一标识符表示,MemoryPersistence设置clientid的保存形式,默认为以内存保存 MqttClient client = new MqttClient(HOST, clientid, new MemoryPersistence()); // MQTT的连接设置 MqttConnectOptions options = new MqttConnectOptions(); // 设置是否清空session,这里如果设置为false表示服务器会保留客户端的连接记录,这里设置为true表示每次连接到服务器都以新的身份连接 options.setCleanSession(true); // 设置连接的用户名 options.setUserName(userName); // 设置连接的密码 options.setPassword(passWord.toCharArray()); // 设置超时时间 单位为秒 options.setConnectionTimeout(10); // 设置会话心跳时间 单位为秒 服务器会每隔1.5*20秒的时间向客户端发送个消息判断客户端是否在线,但这个方法并没有重连的机制 options.setKeepAliveInterval(20); // 设置回调函数 client.setCallback(new MqttCallback() { public void connectionLost(Throwable cause) { System.out.println("connectionLost"); } public void messageArrived(String topic, MqttMessage message) throws Exception { System.out.println("topic:"+topic); System.out.println("Qos:"+message.getQos()); System.out.println("message content:"+new String(message.getPayload())); } public void deliveryComplete(IMqttDeliveryToken token) { System.out.println("deliveryComplete---------"+ token.isComplete()); } }); client.connect(options); //订阅消息 client.subscribe(TOPIC, qos); } catch (Exception e) { e.printStackTrace(); } } } 复制代码