package Mqttmessage;
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import org.eclipse.paho.client.mqttv3.MqttClient;
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import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
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import org.eclipse.paho.client.mqttv3.MqttException;
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/**
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* MQTT客户端工具类
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* 用于连接MQTT服务器并订阅主题
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*/
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public class Client {
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private String host;
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private String topic;
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private String clientId;
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private MqttClient client;
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private MqttConnectOptions options;
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/**
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* 构造函数
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* @param host MQTT服务器地址，格式：tcp://ip:port
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* @param topic 订阅的主题
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* @param clientId 客户端ID，不能重复
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*/
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public Client(String host, String topic, String clientId) {
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this.host = host;
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this.topic = topic;
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this.clientId = clientId;
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this.options = new MqttConnectOptions();
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this.options.setCleanSession(true);
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}
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/**
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* 连接到MQTT服务器
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* @throws MqttException 连接失败时抛出异常
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*/
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public void connect() throws MqttException {
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if (client != null && client.isConnected()) {
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return;
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}
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client = new MqttClient(host, clientId);
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client.connect(options);
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client.setCallback(new PushCallback());
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}
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/**
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* 订阅主题
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* @param qos 服务质量等级，0-2
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* @throws MqttException 订阅失败时抛出异常
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*/
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public void subscribe(int qos) throws MqttException {
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if (client == null || !client.isConnected()) {
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connect();
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}
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client.subscribe(topic, qos);
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}
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/**
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* 订阅主题（默认QoS为2）
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* @throws MqttException 订阅失败时抛出异常
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*/
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public void subscribe() throws MqttException {
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subscribe(2);
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}
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/**
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* 断开连接
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* @throws MqttException 断开连接失败时抛出异常
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*/
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public void disconnect() throws MqttException {
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if (client != null && client.isConnected()) {
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client.disconnect();
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}
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}
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/**
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* 检查是否已连接
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* @return true表示已连接，false表示未连接
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*/
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public boolean isConnected() {
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return client != null && client.isConnected();
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}
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/**
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* 获取MQTT客户端实例
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* @return MqttClient实例
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*/
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public MqttClient getClient() {
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return client;
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}
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/**
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* 示例用法
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*/
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public static void test() {
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try {
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String host = "tcp://39.99.43.227:1883";
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String deiveID="6258";
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String clientId = "hxzkMQTT";
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String clientId2 = "hxzkMQTT2";
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String topic = "mower/"+deiveID+"/gps";
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String topic2 = "mower/"+deiveID+"/response";
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Client mqttClient = new Client(host, topic, clientId);
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Client mqttClient1 = new Client(host, topic2, clientId2);
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mqttClient.connect();
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mqttClient.subscribe();
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mqttClient1.connect();
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mqttClient1.subscribe();
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// 保持程序运行
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//Thread.sleep(Long.MAX_VALUE);
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} catch (MqttException e) {
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throw new RuntimeException(e);
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}
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}
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}
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