一. 代码准备

org.flink.beans.SensorReading

package org.flink.beans;

/**
 * @author 只是甲
 * @date   2021-08-30
 * @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 +
                '}';
    }
}

org.example.SourceTest1_Collection

package org.example;
/**
 * @author 只是甲
 * @date   2021-08-30
 * @remark Flink数据源之从集合读取数据
 */

import org.flink.beans.SensorReading;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;

import java.util.Arrays;

public class SourceTest1_Collection {
    public static void main(String[] args) throws Exception {
        //创建执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);

        // 从集合中读取数据
        DataStream<SensorReading> dataStream = env.fromCollection(Arrays.asList(
                new SensorReading("sensor_1", 1547718199L, 35.8),
                new SensorReading("sensor_6", 1547718201L, 15.4),
                new SensorReading("sensor_7", 1547718202L, 6.7),
                new SensorReading("sensor_10", 1547718205L, 38.1)
        ));

        //DataStream<Integer> integerDataStream = env.fromElements(1, 2, 4, 67, 189);

        //打印输出
        dataStream.print("data");
        //integerDataStream.print();

        //执行
        env.execute();

    }
}

二.运行flink程序

我这边是搭建了CDH 6.3环境，所以flink程序是提交到yarn集群来执行。

flink run -m yarn-cluster -c org.example.SourceTest1_Collection FlinkStudy-1.0-SNAPSHOT.jar

如下截图可以看到，任务执行成功了，但是没有输出

image.png

查询资料得知，DataStream是Task Manager负责输出的，不会输出到终端。

image.png

参考:

1. https://www.bilibili.com/video/BV1qy4y1q728
2. https://ashiamd.github.io/docsify-notes/#/study/BigData/Flink/%E5%B0%9A%E7%A1%85%E8%B0%B7Flink%E5%85%A5%E9%97%A8%E5%88%B0%E5%AE%9E%E6%88%98-%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0?id=_521-%e4%bb%8e%e9%9b%86%e5%90%88%e8%af%bb%e5%8f%96%e6%95%b0%e6%8d%ae
3. https://www.pianshen.com/article/26011976902/