- 简介
- 1.依赖导入
- 2.写入配置文件和配置类
- 3.连接broker核心类和消息发布回调类
- 4.HTTP调用测试发布消息
本文主要介绍怎么用java客户端paho连接emqx并实现共享订阅,所谓共享订阅就是在开多个节点的客户端消费时,保证一条消息有且仅有一个节点消费,不会造成重复消费。
1.依赖导入2.写入配置文件和配置类org.eclipse.paho org.eclipse.paho.client.mqttv3 1.2.0
server:
port: 8082
spring:
mqtt:
username: admin # 账号
password: public # 密码
host-url: tcp://127.0.0.1:1883 # mqtt连接tcp地址
client-id: mq-dky-0813 # 客户端Id，每个启动的id要不同
default-topic: topic-test # 默认主题
timeout: 100 # 超时时间
keepalive: 100
配置类:
package com.lesso.collect_agent.mqtt;
import lombok.Getter;
import lombok.Setter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;
@Component
@ConfigurationProperties("spring.mqtt")
@Setter
@Getter
public class MqttConfig {
@Autowired
private MqttPushClient mqttPushClient;
private String username;
private String password;
private String hostUrl;
private String clientId;
private String defaultTopic;
private int timeout;
private int keepalive;
@Bean
public MqttPushClient getMqttPushClient() {
mqttPushClient.connect(hostUrl, clientId, username, password, timeout, keepalive,defaultTopic);
// 以/#结尾表示订阅所有以test开头的主题
mqttPushClient.subscribe(defaultTopic, 0);
return mqttPushClient;
}
}
3.连接broker核心类和消息发布回调类
package com.lesso.collect_agent.mqtt;
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.stereotype.Component;
@Component
public class MqttPushClient {
private static final Logger logger = LoggerFactory.getLogger(MqttPushClient.class);
private static MqttClient client;
private static MqttClient getClient() {
return client;
}
private static void setClient(MqttClient client) {
MqttPushClient.client = client;
}
public void connect(String host, String clientID, String username, String password, int timeout, int keepalive,String mqttTopic) {
MqttClient client;
try {
client = new MqttClient(host, clientID, new MemoryPersistence());
MqttConnectOptions options = new MqttConnectOptions();
options.setCleanSession(true);
options.setUserName(username);
options.setPassword(password.toCharArray());
options.setConnectionTimeout(timeout);
options.setKeepAliveInterval(keepalive);
// 设置自动重连
options.setAutomaticReconnect(true);
MqttPushClient.setClient(client);
try {
// 此处使用的MqttCallbackExtended类而不是MqttCallback，是因为如果emq服务出现异常导致客户端断开连接后，重连后会自动调用connectComplete方法
client.setCallback(new MqttCallbackExtended() {
@Override
public void connectComplete(boolean reconnect, String serverURI) {
System.out.println("连接完成...");
try {
// 重连后要自己重新订阅topic，这样emq服务发的消息才能重新接收到，不然的话，断开后客户端只是重新连接了服务，并没有自动订阅，导致接收不到消息
client.subscribe(mqttTopic);
logger.info("订阅成功");
}catch (Exception e){
logger.info("订阅出现异常:{}", e);
}
}
@Override
public void connectionLost(Throwable cause) {
System.out.println("失去连接....");
}
@Override
public void messageArrived(String topic, MqttMessage message) throws Exception {
// subscribe后得到的消息会执行到这里面
String content = new String(message.getPayload());
System.out.println("接收消息主题 : " + topic);
System.out.println("接收消息Qos : " + message.getQos());
System.out.println("接收消息内容 : " + content);
// 处理数据
// messageConsumeService.dealEmqContent(content);
}
@Override
public void deliveryComplete(IMqttDeliveryToken token) {
System.out.println("deliveryComplete....");
}
});
client.connect(options);
} catch (Exception e) {
e.printStackTrace();
}
} catch (Exception e) {
e.printStackTrace();
}
}
public void publish(int qos, boolean retained, String topic, String pushMessage) {
MqttMessage message = new MqttMessage();
message.setQos(qos);
message.setRetained(retained);
message.setPayload(pushMessage.getBytes());
MqttTopic mTopic = MqttPushClient.getClient().getTopic(topic);
if (null == mTopic) {
logger.error("topic not exist");
}
MqttDeliveryToken token;
try {
token = mTopic.publish(message);
token.waitForCompletion();
} catch (MqttPersistenceException e) {
e.printStackTrace();
} catch (MqttException e) {
e.printStackTrace();
}
}
public void subscribe(String topic, int qos) {
logger.info("==============开始订阅主题=========" + topic);
try {
MqttPushClient.getClient().subscribe(topic, qos);
} catch (MqttException e) {
e.printStackTrace();
}
}
}
4.HTTP调用测试发布消息
package com.lesso.collect_agent.web;
import com.lesso.collect_agent.mqtt.MqttPushClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("/")
public class PullController {
@Autowired
private MqttPushClient mqttPushClient;
@GetMapping(value = "/publishTopic")
public String publishTopic(String sendMessage) {
System.out.println("message:"+sendMessage);
sendMessage=sendMessage+" : {"name":"ljf","age":345}";
mqttPushClient.publish(0,false,"topic-test",sendMessage);
return "OK";
}
}
暑期编程PK赛
得CSDN机械键盘等精美礼品！
