mqtt的ClientSub

最新推荐文章于 2025-03-03 14:41:49 发布

原创最新推荐文章于 2025-03-03 14:41:49 发布 · 818 阅读

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CC 4.0 BY-SA版权

该博客展示了如何使用IBM的MqttClient类创建一个MQTT客户端并订阅主题。代码中设置了CLEAN_START为true，KEEP_ALIVE时间为30秒，并订阅了"user/2"主题。当消息到达或连接丢失时，都会触发相应的回调处理。

package com.demo.mqtt;

import com.ibm.mqtt.MqttClient;
import com.ibm.mqtt.MqttException;
import com.ibm.mqtt.MqttSimpleCallback;

public class ClientSub {
private final static boolean CLEAN_START = true;
private final static short KEEP_ALIVE = 30;// 低耗网络，但是又需要及时获取数据，心跳30s
private final static String CLIENT_ID = "clientSub";
/**
* @param args
* @throws MqttException
*/
public static void main(String[] args) throws MqttException {
MqttClient mqttClient1 = new MqttClient("tcp://123.57.81.91:1883");
mqttClient1.connect(CLIENT_ID, CLEAN_START, KEEP_ALIVE);

mqttClient1.subscribe(new String[]{"user/2"}, new int[]{2});
mqttClient1.registerSimpleHandler(new MqttSimpleCallback() {

@Override
public void publishArrived(String arg0, byte[] arg1, int arg2, boolean arg3)
throws Exception {
System.out.println(arg0);
System.out.println(new String(arg1));
System.out.println(arg2);
System.out.println(arg3);
}

@Override
public void connectionLost() throws Exception {
System.out.println("4444444444444444444444444444444444444444");
}
});
}

}