package mqtt;
import java.util.concurrent.ScheduledExecutorService;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;
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;
/**
* 模拟一个客户端接收消息
* @author rao
*
*/
public class ClientSearch {
public static String str="";
public static final String HOST = "tcp://172.16.34.181:8848";
//服务器内置主题,用来监测当前服务器上连接的客户端数量($SYS/broker/clients/connected)
public static final String TOPIC1 = "$SYS/broker/clients/connected";
private static final String clientid = "client13";
private MqttClient client;
private MqttConnectOptions options;
private String userName = "admin";
private String passWord = "password";
@SuppressWarnings("unused")
private ScheduledExecutorService scheduler;
public void start() throws MqttException {
// host为主机名,clientid即连接MQTT的客户端ID,一般以唯一标识符表示,MemoryPersistence设置clientid的保存形式,默认为以内存保存
client = new MqttClient(HOST, clientid, new MemoryPersistence());
// MQTT的连接设置
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,设置为true表示每次连接到服务器都以新的身份连接
options.setCleanSession(false);
// 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
client.setCallback(new MqttCallback(){
public void connectionLost(Throwable cause) {
// 连接丢失后,一般在这里面进行重连
// System.out.println("连接断开,可以做重连");
}
public void deliveryComplete(IMqttDeliveryToken token) {
System.out.println("deliveryComplete---------" + token.isComplete());
}
public void messageArrived(String topic, MqttMessage message) throws Exception {
try {
str = message.toString();
// System.out.println(" 从服务器收到的消息为:"+message.toString());
} catch (Exception e) {
e.printStackTrace();
}
}
});
// MqttTopic topic = client.getTopic(TOPIC1);
// setWill方法,如果项目中需要知道客户端是否掉线可以调用该方法。设置最终端口的通知消息
// options.setWill(topic, "close".getBytes(), 2, true); //遗嘱
client.connect(options);
//订阅消息
int[] Qos = {1};
String[] topic1 = {TOPIC1};
client.subscribe(topic1, Qos);
}
@SuppressWarnings("static-access")
//用来给调用处返回消息内容
public String resc() {
return this.str;
}
}