JAVA development MQTT summary
Introduction MQTT
- It is the communication machine-to-machine (M2M), IOT Internet of Things (IoT) commonly used as a lightweight messaging protocol between a machine
- Suitable for low bandwidth applications
- Contains the publication, subscription model, through a proxy server (broker), any one client (client) can subscribe or publish messages to a topic, then clients subscribed to this topic will receive the message
mqtt or so before the company needs to write a demo, recorded here, it was easy to use the time to review, do not involve specific explanation of mqtt, just paste the code and run the process.
Getting MQTT, as well as to explain the features, protocols, structures, see the following article
What is MQTT, it can do, where its application scene? Please refer to the following article
Download MQTT server Apache-Apollo herein used to build the configuration process, please refer to the following article
The following began to create broker,
RaindeMacBook-Pro:bin rain$ ./apollo create mybroker
Creating apollo instance at: mybroker
Generating ssl keystore...
Warning:
JKS 密钥库使用专用格式。建议使用 "keytool -importkeystore -srckeystore keystore -destkeystore keystore -deststoretype pkcs12" 迁移到行业标准格式 PKCS12。
You can now start the broker by executing:
"/Users/rain/Documents/Soft/apache-apollo-1.7.1/bin/mybroker/bin/apollo-broker" run
Or you can run the broker in the background using:
"/Users/rain/Documents/Soft/apache-apollo-1.7.1/bin/mybroker/bin/apollo-broker-service" start
复制代码Into the new generation of broker
RaindeMacBook-Pro:bin rain$ ls
apollo apollo.cmd mybroker testbroker
RaindeMacBook-Pro:bin rain$ cd mybroker/
RaindeMacBook-Pro:mybroker rain$ ls
bin data etc log tmp
RaindeMacBook-Pro:mybroker rain$ cd bin
RaindeMacBook-Pro:bin rain$ ls
apollo-broker apollo-broker-service
复制代码You can see there are two files, start apollo-broker
After the successful launch, you can access the browser, the default user name and password is admin, password
Just go in is, Topics tab is empty, I was shot after running the program, so there is a topic list
Configuring Maven
Add the following configuration in pom.xml
<dependency>
<groupId>org.eclipse.paho</groupId>
<artifactId>org.eclipse.paho.client.mqttv3</artifactId>
<version>1.2.0</version>
</dependency>
复制代码And then create the following class
MqttServer
import org.eclipse.paho.client.mqttv3.*;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
public class MqttServer2 {
/**
* 代理服务器ip地址
*/
public static final String MQTT_BROKER_HOST = "tcp://127.0.0.1:61613";
/**
* 订阅标识
*/
public static final String MQTT_TOPIC = "test2";
private static String userName = "admin";
private static String password = "password";
/**
* 客户端唯一标识
*/
public static final String MQTT_CLIENT_ID = "android_server_xiasuhuei32";
private static MqttTopic topic;
private static MqttClient client;
public static void main(String... args) {
// 推送消息
MqttMessage message = new MqttMessage();
try {
client = new MqttClient(MQTT_BROKER_HOST, MQTT_CLIENT_ID, new MemoryPersistence());
MqttConnectOptions options = new MqttConnectOptions();
options.setCleanSession(true);
options.setUserName(userName);
options.setPassword(password.toCharArray());
options.setConnectionTimeout(10);
options.setKeepAliveInterval(20);
topic = client.getTopic(MQTT_TOPIC);
message.setQos(1);
message.setRetained(false);
message.setPayload("message from server222222".getBytes());
client.connect(options);
while (true) {
MqttDeliveryToken token = topic.publish(message);
token.waitForCompletion();
System.out.println("已经发送222");
Thread.sleep(10000);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
复制代码MqttClient
import org.eclipse.paho.client.mqttv3.*;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
public class MyMqttClient {
/**
* 代理服务器ip地址
*/
public static final String MQTT_BROKER_HOST = "tcp://127.0.0.1:61613";
/**
* 客户端唯一标识
*/
public static final String MQTT_CLIENT_ID = "android_xiasuhuei321";
/**
* 订阅标识
*/
// public static final String MQTT_TOPIC = "xiasuhuei321";
/**
*
*/
public static final String USERNAME = "admin";
/**
* 密码
*/
public static final String PASSWORD = "password";
public static final String TOPIC_FILTER = "test2";
private volatile static MqttClient mqttClient;
private static MqttConnectOptions options;
public static void main(String... args) {
try {
// host为主机名，clientid即连接MQTT的客户端ID，一般以客户端唯一标识符表示，
// MemoryPersistence设置clientid的保存形式，默认为以内存保存
mqttClient = new MqttClient(MQTT_BROKER_HOST, MQTT_CLIENT_ID, new MemoryPersistence());
// 配置参数信息
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，
// 这里设置为true表示每次连接到服务器都以新的身份连接
options.setCleanSession(true);
// 设置用户名
options.setUserName(USERNAME);
// 设置密码
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);
// 连接
mqttClient.connect(options);
// 订阅
mqttClient.subscribe(TOPIC_FILTER);
// 设置回调
mqttClient.setCallback(new MqttCallback() {
@Override
public void connectionLost(Throwable throwable) {
System.out.println("connectionLost");
}
@Override
public void messageArrived(String s, MqttMessage mqttMessage) throws Exception {
System.out.println("Topic: " + s + " Message: " + mqttMessage.toString());
}
@Override
public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
}
复制代码PublishSample
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;
/**
*发布端
*/
public class PublishSample {
public static void main(String[] args) {
String topic = "test2";
String content = "hello 哈哈";
int qos = 1;
String broker = "tcp://127.0.0.1:61613";
String userName = "admin";
String password = "password";
String clientId = "pubClient";
// 内存存储
MemoryPersistence persistence = new MemoryPersistence();
try {
// 创建客户端
MqttClient sampleClient = new MqttClient(broker, clientId, persistence);
// 创建链接参数
MqttConnectOptions connOpts = new MqttConnectOptions();
// 在重新启动和重新连接时记住状态
connOpts.setCleanSession(false);
// 设置连接的用户名
connOpts.setUserName(userName);
connOpts.setPassword(password.toCharArray());
// 建立连接
sampleClient.connect(connOpts);
// 创建消息
MqttMessage message = new MqttMessage(content.getBytes());
// 设置消息的服务质量
message.setQos(qos);
// 发布消息
sampleClient.publish(topic, message);
// 断开连接
sampleClient.disconnect();
// 关闭客户端
sampleClient.close();
} 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();
}
}
}
复制代码SubscribeSample
import org.eclipse.paho.client.mqttv3.*;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
/**
*订阅端
*/
public class SubscribeSample {
public static void main(String[] args) throws MqttException {
String HOST = "tcp://127.0.0.1:61613";
String TOPIC = "test2";
int qos = 1;
String clientid = "subClient";
String userName = "admin";
String passWord = "password";
try {
// host为主机名，test为clientid即连接MQTT的客户端ID，一般以客户端唯一标识符表示，MemoryPersistence设置clientid的保存形式，默认为以内存保存
MqttClient client = new MqttClient(HOST, clientid, new MemoryPersistence());
// MQTT的连接设置
MqttConnectOptions 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，这里设置为true表示每次连接到服务器都以新的身份连接
options.setCleanSession(true);
// 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);
// 设置回调函数
client.setCallback(new MqttCallback() {
public void connectionLost(Throwable cause) {
System.out.println("connectionLost");
}
public void messageArrived(String topic, MqttMessage message) throws Exception {
System.out.println("topic:"+topic);
System.out.println("Qos:"+message.getQos());
System.out.println("message content:"+new String(message.getPayload()));
}
public void deliveryComplete(IMqttDeliveryToken token) {
System.out.println("deliveryComplete---------"+ token.isComplete());
}
});
client.connect(options);
//订阅消息
client.subscribe(TOPIC, qos);
} catch (Exception e) {
e.printStackTrace();
}
}
}
复制代码