Mqtt简单实现发送消息、订阅消息# 系列文章目录
安装好Mosquitto
可查看Mqtt服务器安装
【MQTT】MQTT服务器mosquitto和客户端paho的使用
找到安装路径，双击mosquitto.exe 打开mosquitto
maven引入依赖
<!-- mqtt client -->
<dependency>
<groupId>org.eclipse.paho</groupId>
<artifactId>org.eclipse.paho.client.mqttv3</artifactId>
<version>1.2.5</version>
</dependency>
创建发布客户端 PublishClient.java
使用Mosquitto服务器本机环境，设置mqtt服务器地址为 tcp://127.0.0.1:1883
//mqtt服务器地址
public static final String HOST = "tcp://127.0.0.1:1883";
使用两种方法发送消息，主题为tset/1、test/2
然后每隔10秒循环发送消息，完整代码如下：
//发布客户端
public class PublishClient {
//mqtt服务器地址
public static final String HOST = "tcp://127.0.0.1:1883";
//主题
public static final String TOPIC1 = "test/1";
public static final String TOPIC2 = "test/2";
//mqtt 客户机ID
private static final String clientid = "server";
private MqttClient client;//客户端实例
private MqttTopic topic1;//主题实例
private String userName = "*****"; //非必须
private String passWord = "*****"; //非必须
private MqttMessage message;
//初始化客户端实例
public PublishClient() throws MqttException {
//MemoryPersistence设置clientid的保存形式，默认为以内存保存
client = new MqttClient(HOST, clientid, new MemoryPersistence());
connect();
}
//连接服务器
private void connect() {
//连接配置
MqttConnectOptions options = new MqttConnectOptions();
options.setCleanSession(true);//不保存，每次重启新client
options.setUserName(userName);
options.setPassword(passWord.toCharArray());
// 设置超时时间
options.setConnectionTimeout(10);
// 设置会话心跳时间
options.setKeepAliveInterval(20);
try {
//设置发布回调
client.setCallback(new PublishCallback());
client.connect(options);
topic1 = client.getTopic(TOPIC1);
} catch (Exception e) {
e.printStackTrace();
}
}
//发布1
public void publish(MqttTopic topic, MqttMessage message) throws MqttException,
MqttException {
MqttDeliveryToken token = topic.publish(message);
token.waitForCompletion();
System.out.println("消息已发布! " + token.isComplete());
}
//发布2
public void publish(String topic,MqttMessage message) throws MqttException{
client.publish(topic,message);
System.out.println("消息已发布! ");
}
//测试类
public static void main(String[] args) throws MqttException, InterruptedException {
//发布客户端
PublishClient server = new PublishClient();
boolean toggle =true;
//每隔10s发一条
while (true) {
if(toggle) {
server.message = new MqttMessage();
server.message.setQos(1);//保证消息能到达一次
server.message.setRetained(true);//消息保留
server.message.setPayload(("发布主题:{" + TOPIC1 + "}---菜鸟进阶之路1
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