1、导入依赖库：
implementation 'org.eclipse.paho:org.eclipse.paho.android.service:1.1.1'
implementation 'org.eclipse.paho:org.eclipse.paho.client.mqttv3:1.2.5'
2、功能封装：
package com.example.mqttdemo;import static android.app.Service.START_NOT_STICKY;import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Handler;
import android.os.IBinder;
import android.util.Log;import androidx.annotation.Nullable;import org.eclipse.paho.android.service.MqttAndroidClient;
import org.eclipse.paho.client.mqttv3.*;public class MyMqttService extends Service {public final static String TAG = MyMqttService.class.getSimpleName();public static MqttAndroidClient mqttAndroidClient;private static MqttConnectOptions mMqttConnectOptions;public static String HOST = "tcp://broker.hivemq.com:1883";//服务器地址（协议+地址+端口号）public String USERNAME = "";//用户名public String PASSWORD = "";//密码public static String PUBLISH_TOPIC = "/d";//发布主题public static String RESPONSE_TOPIC = "v";//响应主题public String CLIENTID = "CLIENTID";//设备唯一标识public int onStartCommand(Intent intent, int flags, int startId) {init();return START_NOT_STICKY;//非粘性的 service强制杀死后，不会尝试重新启动service}public IBinder onBind(Intent intent) {return null;}/*** 开启服务*/public static void startService(Context mContext) {mContext.startService(new Intent(mContext, MyMqttService.class));}/*** 发布 （模拟其他客户端发布消息）** @param message 消息*/public static void publish(String message) {String topic = PUBLISH_TOPIC;Integer qos = 1;Boolean retained = false;try {//参数分别为：主题、消息的字节数组、服务质量、是否在服务器保留断开连接后的最后一条消息mqttAndroidClient.publish(topic, message.getBytes(), qos.intValue(), retained.booleanValue());} catch (MqttException e) {e.printStackTrace();}}/*** 响应 （收到其他客户端的消息后，响应给对方告知消息已到达或者消息有问题等）** @param message 消息*/public static void response(String message) {String topic = RESPONSE_TOPIC;Integer qos = 1;Boolean retained = false;try {//参数分别为：主题、消息的字节数组、服务质量、是否在服务器保留断开连接后的最后一条消息mqttAndroidClient.publish(topic, message.getBytes(), qos.intValue(), retained.booleanValue());} catch (MqttException e) {e.printStackTrace();}}/*** 初始化*/private void init() {String serverURI = HOST; //服务器地址（协议+地址+端口号）Log.i(TAG, "初始化MQ" + serverURI);if (mqttAndroidClient == null) {mqttAndroidClient = new MqttAndroidClient(this, serverURI, CLIENTID);mqttAndroidClient.setCallback(mqttCallback); //设置监听订阅消息的回调}if (mMqttConnectOptions == null) {mMqttConnectOptions = new MqttConnectOptions();mMqttConnectOptions.setCleanSession(true); //设置是否清除缓存mMqttConnectOptions.setConnectionTimeout(10); //设置超时时间，单位：秒mMqttConnectOptions.setKeepAliveInterval(20); //设置心跳包发送间隔，单位：秒mMqttConnectOptions.setUserName(USERNAME); //设置用户名mMqttConnectOptions.setPassword(PASSWORD.toCharArray()); //设置密码}// last will messageboolean doConnect = true;String message = "{\"terminal_uid\":\"" + CLIENTID + "\"}";String topic = PUBLISH_TOPIC;Integer qos = 1;Boolean retained = true;if ((!message.equals("")) || (!topic.equals(""))) {// 最后的遗嘱try {mMqttConnectOptions.setWill(topic, message.getBytes(), qos.intValue(), retained.booleanValue());} catch (Exception e) {Log.i(TAG, "Exception Occured");doConnect = false;iMqttActionListener.onFailure(null, e);}}if (doConnect) {doClientConnection();}}/*** 连接MQTT服务器*/private static void doClientConnection() {try {if (!mqttAndroidClient.isConnected() && isConnectIsNomarl()) {Log.i(TAG, "连接MQTT服务器" + HOST);mqttAndroidClient.connect(mMqttConnectOptions, null, iMqttActionListener);}} catch (Exception e) {e.printStackTrace();}}/*** 判断网络是否连接*/private static boolean isConnectIsNomarl() {return true;
// ConnectivityManager connectivityManager = (ConnectivityManager) BaseApplication.getInstance().getSystemService(Context.CONNECTIVITY_SERVICE);
// NetworkInfo info = connectivityManager.getActiveNetworkInfo();
// if (info != null && info.isAvailable()) {
// String name = info.getTypeName();
// Log.i(TAG, "当前网络名称：" + name);
// return true;
// } else {
// Log.i(TAG, "没有可用网络");
// /*没有可用网络的时候，延迟3秒再尝试重连*/
// new Handler().postDelayed(new Runnable() {
// @Override
// public void run() {
// Log.i(TAG, "没有可用网络doClientConnection");
// doClientConnection();
// }
// }, 3000);
// return false;
// }}//MQTT是否连接成功的监听private static IMqttActionListener iMqttActionListener = new IMqttActionListener() {public void onSuccess(IMqttToken arg0) {Log.i(TAG, "连接成功 " + HOST);try {if (mqttAndroidClient != null) {mqttAndroidClient.subscribe(PUBLISH_TOPIC, 1);//订阅主题，参数：主题、服务质量}} catch (Exception e) {e.printStackTrace();}}public void onFailure(IMqttToken arg0, Throwable arg1) {arg1.printStackTrace();Log.i(TAG, "连接失败 ");doClientConnection();//连接失败，重连（可关闭服务器进行模拟）}};//订阅主题的回调private MqttCallback mqttCallback = new MqttCallback() {public void messageArrived(String topic, MqttMessage msgStr) throws Exception {try {String enCodeMsg = new String(msgStr.getPayload());Log.i(TAG, "收到消息： " + enCodeMsg);//收到消息，这里弹出Toast表示。如果需要更新UI，可以使用广播或者EventBus进行发送//收到其他客户端的消息后，响应给对方告知消息已到达或者消息有问题等response("message arrived");} catch (Exception e) {e.printStackTrace();}}public void deliveryComplete(IMqttDeliveryToken arg0) {}public void connectionLost(Throwable arg0) {Log.i(TAG, "连接断开 ");doClientConnection();//连接断开，重连}};public static void disconnect(Context context) {try {if (mqttAndroidClient != null && mqttAndroidClient.isConnected()) {mqttAndroidClient.unsubscribe(PUBLISH_TOPIC);mqttAndroidClient.unregisterResources();mqttAndroidClient.disconnect(0); //断开连接mqttAndroidClient = null;context.stopService(new Intent(context, MyMqttService.class));}} catch (Exception e) {e.printStackTrace();}}
}
