Flink-04 Flink Java 3分钟上手 FlinkKafkaConsumer消费Kafka数据 进行计算SingleOutputStreamOperatorDataStreamSource 原创

代码仓库

会同步代码到 GitHub
https://github.com/turbo-duck/flink-demo

pom.xml

修改pom.xml，需要加入 kafka相关的包，和适配器。

<?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.example</groupId>
    <artifactId>flink-demo-01</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <flink.version>1.13.2</flink.version>
        <scala.binary.version>2.12</scala.binary.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-java</artifactId>
            <version>${flink.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-streaming-java_${scala.binary.version}</artifactId>
            <version>${flink.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-clients_${scala.binary.version}</artifactId>
            <version>${flink.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.flink</groupId>
            <artifactId>flink-connector-kafka_2.11</artifactId>
            <version>${flink.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.kafka</groupId>
            <artifactId>kafka-clients</artifactId>
            <version>3.0.0</version>
        </dependency>
    </dependencies>
</project>

编写代码

设置 Kafka 配置

Properties properties = new Properties();
properties.setProperty("bootstrap.servers", "0.0.0.0:9092");

创建Kafka消费者

FlinkKafkaConsumer<String> consumer = new FlinkKafkaConsumer<>("test", new SimpleStringSchema(), properties);

添加数据源

DataStreamSource<String> data = env.addSource(consumer);

FlatMap

SingleOutputStreamOperator<Tuple2<String, Long>> wordAndOne = data.flatMap(new FlatMapFunction<String, Tuple2<String, Long>>() {
    public void flatMap(String s, Collector<Tuple2<String, Long>> collector) throws Exception {
        for (String word : s.split(" ")) {
            collector.collect(Tuple2.of(word, 1L));
        }
    }
});

计算求和

SingleOutputStreamOperator<Tuple2<String, Long>> result = wordAndOne
    .keyBy(new KeySelector<Tuple2<String, Long>, Object>() {
        @Override
        public Object getKey(Tuple2<String, Long> value) throws Exception {
            return value.f0;
        }
    })
    .sum(1);

全部代码

package icu.wzk.demo04;

import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.common.serialization.SimpleStringSchema;
import org.apache.flink.api.java.functions.KeySelector;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.connectors.kafka.FlinkKafkaConsumer;
import org.apache.flink.util.Collector;

import java.util.Properties;

public class StartApp {

    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        Properties properties = new Properties();
        properties.setProperty("bootstrap.servers","0.0.0.0:9092");
        FlinkKafkaConsumer<String> consumer = new FlinkKafkaConsumer<>("test", new SimpleStringSchema(), properties);
        DataStreamSource<String> data = env.addSource(consumer);
        SingleOutputStreamOperator<Tuple2<String, Long>> wordAndOne = data.flatMap(new FlatMapFunction<String, Tuple2<String, Long>>() {
            public void flatMap(String s, Collector<Tuple2<String, Long>> collector) throws Exception {
                for (String word : s.split(" ")) {
                    collector.collect(Tuple2.of(word, 1L));
                }
            }
        });
        SingleOutputStreamOperator<Tuple2<String, Long>> result = wordAndOne
                .keyBy(new KeySelector<Tuple2<String, Long>, Object>() {
                    @Override
                    public Object getKey(Tuple2<String, Long> value) throws Exception {
                        return value.f0;
                    }
                })
                .sum(1);
        result.print();
        env.execute();
    }

}

KafkaProducer

package icu.wzk.demo04;

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;

import java.util.Properties;

public class TestKafkaProducer {

    public static void main(String[] args) throws InterruptedException {
        Properties props = new Properties();
        props.put("bootstrap.servers", "0.0.0.0:9092");
        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        Producer<String, String> producer = new KafkaProducer<>(props);
        for (int i = 0; i < 500; i++) {
            String key = "key-" + i;
            String value = "value-" + i;
            ProducerRecord<String, String> record = new ProducerRecord<>("test", key, value);
            producer.send(record);
            System.out.println("send: " + key);
            Thread.sleep(200);
        }
        producer.close();
    }

}