Java 如何访问主方法EclipsePAHO中回调方法(MessageArrized)的消息到达的有效负载?
问题陈述:-我正在尝试自动化MQTT流,为此我需要按顺序发布和订阅多个主题。诀窍在于,从第一次发布接收到的消息具有一些值,这些值将在下一个sub/pub命令中传递 例如Java 如何访问主方法EclipsePAHO中回调方法(MessageArrized)的消息到达的有效负载?,java,mqtt,iot,paho,Java,Mqtt,Iot,Paho,问题陈述:-我正在尝试自动化MQTT流,为此我需要按顺序发布和订阅多个主题。诀窍在于,从第一次发布接收到的消息具有一些值,这些值将在下一个sub/pub命令中传递 例如 分包至topicA/abc 酒吧至topicA/abc topicA/abc上收到的消息是xyz 主题topicA/xyz的子主题 发布到主题topicA/xyz 我能够在第一个主题上接收消息,但我不知道如何在main方法中访问接收到的消息的有效负载,并将其传递并附加到下一个子主题 是否有一种方法可以将从messageArriv
public class MqttOverSSL {
String deviceId;
MqttClient client = null;
public MqttOverSSL() {
}
public MqttOverSSL(String deviceId) throws MqttException, InterruptedException {
this.deviceId = deviceId;
MqttConnection mqttConObj = new MqttConnection();
this.client = mqttConObj.mqttConnection();
}
public void getLinkCodeMethod() throws MqttException, InterruptedException {
client.subscribe("abc/multi/" + deviceId + "/linkcode", 0);
publish(client, "abc/multi/" + deviceId + "/getlinkcode", 0, "".getBytes());
}
}
Mqtt回显:-
public class SimpleMqttCallBack implements MqttCallback {
String arrivedMessage;
@Override
public void connectionLost(Throwable throwable) {
System.out.println("Connection to MQTT broker lost!");
}
@Override
public void messageArrived(String s, MqttMessage mqttMessage) throws Exception {
arrivedMessage = mqttMessage.toString();
System.out.println("Message received:\t" + arrivedMessage);
linkCode(arrivedMessage);
}
@Override
public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {
System.out.println("Delivery complete callback: Publish Completed "+ Arrays.toString(iMqttDeliveryToken.getTopics()));
}
public void linkCode(String arrivedMessage) throws MqttException {
System.out.println("String is "+ arrivedMessage);
Gson g = new Gson();
GetCode code = g.fromJson(arrivedMessage, GetCode.class);
System.out.println(code.getLinkCode());
}
}
出版商类别:-
public class Publisher {
public static void publish(MqttClient client, String topicName, int qos, byte[] payload) throws MqttException {
String time = new Timestamp(System.currentTimeMillis()).toString();
log("Publishing at: "+time+ " to topic \""+topicName+"\" qos "+qos);
// Create and configure a message
MqttMessage message = new MqttMessage(payload);
message.setQos(qos);
// Send the message to the server, control is not returned until
// it has been delivered to the server meeting the specified
// quality of service.
client.publish(topicName, message);
}
static private void log(String message) {
boolean quietMode = false;
if (!quietMode) {
System.out.println(message);
}
}
}
好的,你现在想做的事情就更清楚了 简短回答否,不能将值传递回“主方法”。MQTT是异步的,这意味着您不知道订阅主题的消息何时到达
您需要更新代码以处理检查传入消息主题是什么,然后在
messageArrived()
处理程序中处理您希望对该响应执行的任何操作。如果你有一系列的任务要做,那么你可能需要实现所谓的状态机,以便跟踪你在序列中的位置。如果不与我们共享任何代码,我们真的无法帮助Hi hardilib,在原始帖子中添加了相同的代码。请看一看。