一、代码准备
org.flink.beans.SensorReading
package org.flink.beans;
/**
* @remark 传感器温度读数的数据类型
*/
public class SensorReading {
// 属性：id，时间戳，温度值
private String id;
private Long timestamp;
private Double temperature;
public SensorReading() {
}
public SensorReading(String id, Long timestamp, Double temperature) {
this.id = id;
this.timestamp = timestamp;
this.temperature = temperature;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public Long getTimestamp() {
return timestamp;
}
public void setTimestamp(Long timestamp) {
this.timestamp = timestamp;
}
public Double getTemperature() {
return temperature;
}
public void setTemperature(Double temperature) {
this.temperature = temperature;
}
@Override
public String toString() {
return "SensorReading{" +
"id='" + id + '\'' +
", timestamp=" + timestamp +
", temperature=" + temperature +
'}';
}
}
SourceTest4_UDF
package org.example;
import org.flink.beans.SensorReading;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.source.SourceFunction;
import java.util.HashMap;
import java.util.Random;
/**
* @remark Flink之自定义Source
*/
public class SourceTest4_UDF {
public static void main(String[] args) throws Exception{
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setParallelism(1);
// 从文件读取数据
DataStream<SensorReading> dataStream = env.addSource( new MySensorSource() );
// 打印输出
dataStream.print();
env.execute();
}
// 实现自定义的SourceFunction
public static class MySensorSource implements SourceFunction<SensorReading>{
// 定义一个标识位，用来控制数据的产生
private boolean running = true;
@Override
public void run(SourceContext<SensorReading> ctx) throws Exception {
// 定义一个随机数发生器
Random random = new Random();
// 设置10个传感器的初始温度
HashMap<String, Double> sensorTempMap = new HashMap<>();
for( int i = 0; i < 10; i++ ){
sensorTempMap.put("sensor_" + (i+1), 60 + random.nextGaussian() * 20);
}
while (running){
for( String sensorId: sensorTempMap.keySet() ){
// 在当前温度基础上随机波动
Double newtemp = sensorTempMap.get(sensorId) + random.nextGaussian();
sensorTempMap.put(sensorId, newtemp);
ctx.collect(new SensorReading(sensorId, System.currentTimeMillis(), newtemp));
}
// 控制输出频率
Thread.sleep(2000L);
}
}
@Override
public void cancel() {
running = false;
}
}}
二、运行程序
运行程序截图:
