mqtt入门（四）：客户端sdk
前言
- 该笔记学习自mqtt
起步
- 导入依赖
<dependency>
<groupId>org.eclipse.paho</groupId>
<artifactId>org.eclipse.paho.client.mqttv3</artifactId>
<version>1.2.2</version>
</dependency>
- 配置yml
mqtt:
broker-url: tcp://124.xxx.xxx.xxx:1883
client-id: emq-client
username: user
password: 123456
- 获取配置
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;
@Configuration
@ConfigurationProperties(prefix = "mqtt")
public class MqttProperties {
private String brokerUrl;
private String clientId;
private String username;
private String password;
public String getBrokerUrl() {
return brokerUrl;
}
public void setBrokerUrl(String brokerUrl) {
this.brokerUrl = brokerUrl;
}
public String getClientId() {
return clientId;
}
public void setClientId(String clientId) {
this.clientId = clientId;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "MqttProperties{" +
"brokerUrl='" + brokerUrl + '\'' +
", clientId='" + clientId + '\'' +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
- 编写客户端
import com.itheima.mqtt.enums.QosEnum;
import com.itheima.mqtt.properties.MqttProperties;
import org.eclipse.paho.client.mqttv3.*;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
@Component
public class EmqClient {
private static final Logger log = LoggerFactory.getLogger(EmqClient.class);
private IMqttClient mqttClient;
@Autowired
private MqttProperties mqttProperties;
@Autowired
private MqttCallback mqttCallback;
@PostConstruct
public void init(){
MqttClientPersistence mempersitence = new MemoryPersistence();
try {
mqttClient = new MqttClient(mqttProperties.getBrokerUrl(),mqttProperties.getClientId(),mempersitence);
} catch (MqttException e) {
log.error("初始化客户端mqttClient对象失败,errormsg={},brokerUrl={},clientId={}",e.getMessage(),mqttProperties.getBrokerUrl(),mqttProperties.getClientId());
}
}
/**
* 连接broker
* @param username
* @param password
*/
public void connect(String username,String password){
MqttConnectOptions options = new MqttConnectOptions();
options.setAutomaticReconnect(true);
options.setUserName(username);
options.setPassword(password.toCharArray());
options.setCleanSession(true);
mqttClient.setCallback(mqttCallback);
try {
mqttClient.connect(options);
} catch (MqttException e) {
log.error("mqtt客户端连接服务端失败,失败原因{}",e.getMessage());
}
}
/**
* 断开连接
*/
@PreDestroy
public void disConnect(){
try {
mqttClient.disconnect();
} catch (MqttException e) {
log.error("断开连接产生异常,异常信息{}",e.getMessage());
}
}
/**
* 重连
*/
public void reConnect(){
try {
mqttClient.reconnect();
} catch (MqttException e) {
log.error("重连失败,失败原因{}",e.getMessage());
}
}
/**
* 发布消息
* @param topic
* @param msg
* @param qos
* @param retain
*/
public void publish(String topic, String msg, QosEnum qos,boolean retain){
MqttMessage mqttMessage = new MqttMessage();
mqttMessage.setPayload(msg.getBytes());
mqttMessage.setQos(qos.value());
mqttMessage.setRetained(retain);
try {
mqttClient.publish(topic,mqttMessage);
} catch (MqttException e) {
log.error("发布消息失败,errormsg={},topic={},msg={},qos={},retain={}",e.getMessage(),topic,msg,qos.value(),retain);
}
}
/**
* 订阅
* @param topicFilter
* @param qos
*/
public void subscribe(String topicFilter,QosEnum qos){
try {
mqttClient.subscribe(topicFilter,qos.value());
} catch (MqttException e) {
log.error("订阅主题失败,errormsg={},topicFilter={},qos={}",e.getMessage(),topicFilter,qos.value());
}
}
/**
* 取消订阅
* @param topicFilter
*/
public void unSubscribe(String topicFilter){
try {
mqttClient.unsubscribe(topicFilter);
} catch (MqttException e) {
log.error("取消订阅失败,errormsg={},topicfiler={}",e.getMessage(),topicFilter);
}
}
}
- 编写枚举类
public enum QosEnum {
QoS0(0),QoS1(1),QoS2(2);
private final int value;
QosEnum(int value) {
this.value = value;
}
public int value(){
return this.value;
}
}
- 编写回调类
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
@Component
public class MessageCallback implements MqttCallback {
private static final Logger log = LoggerFactory.getLogger(MessageCallback.class);
/**
* 丢失了对服务端的连接后触发的回调
* @param cause
*/
@Override
public void connectionLost(Throwable cause) {
// 资源的清理 重连
log.info("丢失了对服务端的连接");
}
/**
* 应用收到消息后触发的回调
* @param topic
* @param message
* @throws Exception
*/
@Override
public void messageArrived(String topic, MqttMessage message) throws Exception {
log.info("订阅者订阅到了消息,topic={},messageid={},qos={},payload={}",
topic,
message.getId(),
message.getQos(),
new String(message.getPayload()));
}
/**
* 消息发布者消息发布完成产生的回调
* @param token
*/
@Override
public void deliveryComplete(IMqttDeliveryToken token) {
int messageId = token.getMessageId();
String[] topics = token.getTopics();
log.info("消息发布完成,messageid={},topics={}",messageId,topics);
}
}
- 编写测试类
import com.itheima.mqtt.client.EmqClient;
import com.itheima.mqtt.enums.QosEnum;
import com.itheima.mqtt.properties.MqttProperties;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
@RestController
public class TestController {
@Autowired
private EmqClient emqClient;
@Autowired
private MqttProperties properties;
@RequestMapping("/test1")
@ResponseBody
public String test1(){
//连接服务端
emqClient.connect(properties.getUsername(),properties.getPassword());
// 发布消息
emqClient.publish("testtopic/123"," publish msg :"+ LocalDateTime.now().format(DateTimeFormatter.ISO_DATE_TIME),
QosEnum.QoS2,false);
//订阅一个主题
//emqClient.subscribe("testtopic/#", QosEnum.QoS2);
return "success";
}
}
-
启动项目测试
-
向服务端发送一条消息
-
MQTTX订阅消息
-
vue + mqtt参考
