flink 计数器-笔记
flink 计数器
flink source 中设置计数器
https://blog.csdn.net/yy8623977/article/details/119767594
https://blog.csdn.net/weixin_44844089/article/details/103987818
Scala中最佳的JSON库 - play-json 生产实践经验分享
https://blog.csdn.net/chaizepeng/article/details/118407487
https://blog.csdn.net/weixin_30646505/article/details/94767884
https://blog.csdn.net/liuhui_306/article/details/51777471
play-json
https://www.jianshu.com/p/20b9c701cb90
play-json pom
<!-- paly json : 解析json -->
<!-- https://mvnrepository.com/artifact/com.typesafe.play/play-json -->
<dependency>
<groupId>com.typesafe.play</groupId>
<artifactId>play-json_2.12</artifactId>
<version>2.9.2</version>
</dependency>
demo MqttPublisher
package com.hs.fast.test
/**
* @Title:
* @BelongProjecet hs_flink_elephant
* @BelongPackage com.hs.fast.test
* @Description:
* @Copyright time company - Powered By 研发一部
* @Author: cw
* @Date: 2023-11-1 11:07
* @Version V1.0
*/
import org.eclipse.paho.client.mqttv3._
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence
import play.api.libs.json._
object MqttPublisher {
def main(args: Array[String]): Unit = {
val brokerUrl = "tcp://192.168.33.22:1883"
val clientId = "mqtt-publisher"
val username="cw";
val password="flink-123456";
// val clientId = "mqtt-publisher"
val topic = "topic/A"
val persistence = new MemoryPersistence()
val client = new MqttClient(brokerUrl, clientId, persistence)
val options = new MqttConnectOptions()
options.setCleanSession(true)
options.setUserName(username)
options.setPassword(password.toCharArray)
println("Connecting to broker: " + brokerUrl)
client.connect(options)
println("Connected")
// 循环发送JSON数据
var counter = 0
while (true) {
val json = Json.obj(
"counter" -> counter,
"message" -> "Hello MQTT"
)
val payload = json.toString().getBytes("UTF-8")
val message = new MqttMessage(payload)
client.publish(topic, message)
println(s"Published message: $json")
counter += 1
Thread.sleep(1000) // 每隔1秒发送一次
}
client.disconnect()
println("Disconnected")
}
}
scala中break与continue的实现
https://blog.csdn.net/do_yourself_go_on/article/details/74562517
//必须引入这个类下面的方法，用于实现break功能
import util.control.Breaks._
object BreakableTest extends App{
val list1 = List(1,2,3,4,5)
//breakable方法与break方法组合使用实现break功能
//将整个循环放置于breakable方法中，然后需要跳出循环的时候则使用break方法，则跳出整个循环
breakable{
println("break功能展示：——————————————")
for(i <- list1){
if(i==4) break else println(i)
}
}
}
mqttv3 subscribe many topic
org.eclipse.paho.client.mqttv3.MqttClient#subscribe(java.lang.String[])
Scala中使用Flink连接到MQTT并实现重连和重订阅
要在Scala中使用Flink连接到MQTT并实现重连和重订阅，可以使用Flink的MqttSource和MqttSink，并结合使用Flink的可重试连接器来实现。
首先，确保你已经添加了Flink的Mqtt依赖。在build.sbt文件中添加以下依赖项：
libraryDependencies += "org.apache.flink" %% "flink-connector-mqtt" % "1.13.0"
然后，可以使用以下代码示例来实现：
import org.apache.flink.streaming.api.scala._
import org.apache.flink.streaming.connectors.mqtt._
import org.apache.flink.streaming.connectors.mqtt.internal.MqttConnectionConfig
import org.apache.flink.streaming.connectors.mqtt.MqttSource
import org.apache.flink.streaming.connectors.mqtt.MqttSource.ReconnectionStrategy
object MqttSourceExample {
def main(args: Array[String]): Unit = {
val env = StreamExecutionEnvironment.getExecutionEnvironment
val connectionConfig = new MqttConnectionConfig.Builder()
.setClientId("your-client-id")
.setServerHost("your-mqtt-server-host")
.setServerPort(1883)
.setCleanSession(true)
.build()
val mqttSource = new MqttSource[String](
connectionConfig,
ReconnectionStrategy.CONNECT,
new SimpleStringSchema
)
val stream = env.addSource(mqttSource)
// 在回调函数中实现重连和重订阅
stream.map { value =>
// 处理接收到的消息
value
}
env.execute("MqttSourceExample")
}
}
在上面的示例中，你需要替换以下参数：
your-client-id：你的MQTT客户端ID。your-mqtt-server-host：你的MQTT服务器主机名或IP地址。
在回调函数中，你可以根据需要实现重连和重订阅的逻辑。例如，你可以在发生连接断开时重新连接，并在重新连接后重新订阅主题。
请注意，上述示例仅提供了一个基本的框架，你需要根据你的实际需求进行适当的修改和扩展。
Scala中实现MQTT回调函数返回主题和消息内容
https://blog.csdn.net/weixin_43222122/article/details/114586944
要在Scala中实现MQTT回调函数返回主题和消息内容，你可以使用Eclipse Paho MQTT客户端库。以下是一个示例代码：
import org.eclipse.paho.client.mqttv3._
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence
object MqttCallbackExample {
def main(args: Array[String]): Unit = {
val broker = "tcp://mqtt.eclipse.org:1883"
val clientId = "your-client-id"
val topic = "your-topic"
val persistence = new MemoryPersistence
val client = new MqttClient(broker, clientId, persistence)
val callback = new MqttCallback {
override def connectionLost(cause: Throwable): Unit = {
println("Connection lost: " + cause.getMessage)
}
override def messageArrived(topic: String, message: MqttMessage): Unit = {
val content = new String(message.getPayload)
println("Received message from topic: " + topic)
println("Message content: " + content)
}
override def deliveryComplete(token: IMqttDeliveryToken): Unit = {
// Not used in this example
}
}
client.setCallback(callback)
val options = new MqttConnectOptions
options.setCleanSession(true)
client.connect(options)
client.subscribe(topic)
// 等待消息到达
Thread.sleep(5000)
client.disconnect()
client.close()
}
}
在上面的示例中，你需要替换以下参数：
broker：MQTT代理服务器的地址。clientId：你的MQTT客户端ID。topic：要订阅的主题。
在回调函数的messageArrived方法中，你可以获取到接收到的消息的主题和内容。你可以根据需要对消息进行处理。
请注意，上述示例仅提供了一个基本的框架，你需要根据你的实际需求进行适当的修改和扩展。
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