STM32+W5500+MQTT+Android实现远程数据采集及控制

一旦连接成功，如图4.2选择TCP =>

一旦连接成功，选择TCP =>完整工程代码可在后面的附件下载。

2 手机端代码实现
手机端我们也使用官方提供的Java库Java client and utilities，下载地址：
http://www.eclipse.org/paho/
将jar文件添加到工程中即可，程序界面如下所示：

上面4个条目分别显示STM32单片机通过W5500发送到服务器端的传感器测量数据；
下面4个图片分别控制板子上的4个LED灯；
消息发送我们采用线程的方式发送，接收采用回调函数方式接收消息。

2.1 实现消息发送
发送消息的代码如下所示：

class PublishThread extends Thread {
String topic;
MqttMessage message;
int qos = 0;
MemoryPersistence persistence = new MemoryPersistence();
PublishThread(String topic,String message){
this.topic = topic;
this.message = new MqttMessage(message.getBytes());
}
public void sendMessage(String topic,String message){
this.topic = topic;
this.message = new MqttMessage(message.getBytes());
run();
}
@Override
public void run() {
try {
MqttClient sampleClient = new MqttClient(broker, clientId, persistence);
MqttConnectOptions connOpts = new MqttConnectOptions();
connOpts.setCleanSession(true);
connOpts.setKeepAliveInterval(1);
System.out.println(“Connecting to broker: ” + broker);
sampleClient.connect(connOpts);
System.out.println(“Connected”);
System.out.println(“Publishing message: ” + message.toString());
message.setQos(qos);
sampleClient.publish(topic, message);
System.out.println(“Message published”);
sampleClient.disconnect();
System.out.println(“Disconnected”);
}catch(MqttException me) {
System.out.println(“reason “+me.getReasonCode());
System.out.println(“msg “+me.getMessage());
System.out.println(“loc “+me.getLocalizedMessage());
System.out.println(“cause “+me.getCause());
System.out.println(“excep “+me);
me.printStackTrace();
}
}
}

2.2 实现消息接收
接收消息的代码如下所示：

class SubscribeThread extends Thread{
final String topic;
MemoryPersistence persistence = new MemoryPersistence();
SubscribeThread(String topic){
this.topic = topic;
}
@Override
public void run(){
try {
final MqttClient sampleClient = new MqttClient(broker, clientId, persistence);
final MqttConnectOptions connOpts = new MqttConnectOptions();
connOpts.setCleanSession(true);
System.out.println(“Connecting to broker: ” + broker);
connOpts.setKeepAliveInterval(5);
sampleClient.setCallback(new MqttCallback() {
@Override
public void connectionLost(Throwable throwable) {
System.out.println(“connectionLost”);
try {
sampleClient.connect(connOpts);
sampleClient.subscribe(topic);
}catch (MqttException e){
e.printStackTrace();
}
}

@Override
public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {
System.out.println(“messageArrived:”+mqttMessage.toString());
System.out.println(topic);
System.out.println(mqttMessage.toString());
try {
JSONTokener jsonParser = new JSONTokener(mqttMessage.toString());
JSONObject person = (JSONObject) jsonParser.nextValue();
temperature = person.getDouble(“temperature”);
humidity = person.getDouble(“humidity”);
light = person.getDouble(“light”);
pressure = person.getDouble(“pressure”);
System.out.println(“temperature = ” + temperature);
System.out.println(“humidity = ” + humidity);
runOnUiThread(new Runnable() {
@Override
public void run() {
temperatureTextView.setText(String.format(“%.1f”, temperature));
humidityTextView.setText(String.format(“%.1f”, humidity));
lightTextView.setText(String.format(“%.1f”, light));
pressureTextView.setText(String.format(“%.1f”, pressure));
}
});
} catch (JSONException ex) {
ex.printStackTrace();
}
}

@Override
public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {
System.out.println(“deliveryComplete”);
}
});
sampleClient.connect(connOpts);
sampleClient.subscribe(topic);
} catch(MqttException me) {
System.out.println(“reason “+me.getReasonCode());
System.out.println(“msg “+me.getMessage());
System.out.println(“loc “+me.getLocalizedMessage());
System.out.println(“cause “+me.getCause());
System.out.println(“excep “+me);
me.printStackTrace();
}
}
}