Flink Sink Kafka

原创转载请注明出处：https://www.cnblogs.com/agilestyle/p/15149998.html

Kafka Setup

wget https://downloads.apache.org/kafka/2.8.0/kafka_2.12-2.8.0.tgz

tar zxvf kafka_2.12-2.8.0.tgz -C ~/app

cd ~/app/kafka_2.12-2.8.0

# start the zookeeper service
bin/zookeeper-server-start.sh config/zookeeper.properties

# start the Kafka broker service
bin/kafka-server-start.sh config/server.properties

# create topic
bin/kafka-topics.sh --create --topic flink_topic --bootstrap-server localhost:9092

# describle message
bin/kafka-topics.sh --describe --topic flink_topic --bootstrap-server localhost:9092

# produce message
bin/kafka-console-producer.sh --topic flink_topic --bootstrap-server localhost:9092

# consumer message
bin/kafka-console-consumer.sh --topic flink_topic --from-beginning --bootstrap-server localhost:9092

Maven Dependency

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.fool</groupId>
    <artifactId>flink</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-java</artifactId>
            <version>1.12.5</version>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-java_2.12</artifactId>
            <version>1.12.5</version>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-clients_2.12</artifactId>
            <version>1.12.5</version>
        </dependency>

        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-connector-kafka_2.12</artifactId>
            <version>1.12.1</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.20</version>
        </dependency>

    </dependencies>

</project>

SRC

src/main/java/org/fool/flink/contract/Sensor.java

package org.fool.flink.contract;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Sensor {
    private String id;
    private Long timestamp;
    private Double temperature;
}

src/main/java/org/fool/flink/sink/SinkKafkaTest.java

package org.fool.flink.sink;

import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.common.serialization.SimpleStringSchema;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducer;
import org.fool.flink.contract.Sensor;

import java.util.Objects;
import java.util.Properties;

public class SinkKafkaTest {
    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment environment = StreamExecutionEnvironment.getExecutionEnvironment();
        environment.setParallelism(1);

        Properties properties = new Properties();
        properties.setProperty("bootstrap.servers", "localhost:9092");
        properties.setProperty("group.id", "consumer-group");
        properties.setProperty("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        properties.setProperty("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        properties.setProperty("auto.offset.reset", "latest");

        String inputPath = Objects.requireNonNull(ClassLoader.getSystemClassLoader().getResource("sensor.txt")).getPath();

        DataStream<String> inputStream = environment.readTextFile(inputPath);

        DataStream<String> dataStream = inputStream.map(new MapFunction<String, String>() {
            @Override
            public String map(String value) throws Exception {
                String[] fields = value.split(",");
                return new Sensor(fields[0], new Long(fields[1]), new Double(fields[2])).toString();
            }
        });

        dataStream.addSink(new FlinkKafkaProducer<>("flink_topic", new SimpleStringSchema(), properties));

        environment.execute();
    }
}

src/main/resources/sensor.txt

1,1628754086,35.8
2,1628754096,36.8
3,1628754106,37.8
4,1628754116,38.8
1,1628754186,36.6
2,1628754296,36.6
3,1628754306,37.6
4,1628754416,38.6
1,1628754986,25.8
1,1628754086,39.6
2,1628754996,26.8
3,1628754906,27.8
4,1628754916,28.8

Run

Console Output

Kafka Consumer

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