Kafka Producer

Send "Hello World!" string to topic named "first-topic".

Producer sends a data to Consumer asynchronous, so we have to flush to see results right away.

Execute below command to see "Hello World!"

>> kafka-console-consumer --bootstrap-server localhost:9092 --topic first-topic --group group-one

kafkaStudies.iml

+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4" />
\ No newline at end of file

pom.xml

+<?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>csw.kafka</groupId>
+    <artifactId>kafkaStudies</artifactId>
+    <version>1.0</version>
+    <!-- https://mvnrepository.com/artifact/org.apache.kafka/kafka-clients -->
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.kafka</groupId>
+            <artifactId>kafka-clients</artifactId>
+            <version>2.6.0</version>
+        </dependency>
+
+        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>1.7.30</version>
+        </dependency>
+
+        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-simple -->
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-simple</artifactId>
+            <version>1.7.30</version>
+<!--            <scope>test</scope>-->
+        </dependency>
+
+        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.11.3</version>
+        </dependency>
+
+    </dependencies>
+
+
+</project>
\ No newline at end of file

src/main/java/csw/kafka/study/lesson1/ProducerDemo.java

+package csw.kafka.study.lesson1;
+
+import org.apache.kafka.clients.producer.KafkaProducer;
+import org.apache.kafka.clients.producer.ProducerConfig;
+import org.apache.kafka.clients.producer.ProducerRecord;
+import org.apache.kafka.common.serialization.StringSerializer;
+
+import java.util.Properties;
+
+public class ProducerDemo {
+    public static void main(String[] args) {
+        String myServer = "localhost:9092";
+
+        // Kafka Producer 설정
+        Properties properties = new Properties();
+        properties.setProperty(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, myServer);
+        properties.setProperty(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
+        properties.setProperty(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
+        // Kafka는 데이터를 바이트로 보냄 (0,1)
+
+        // Kafka Producer Record
+        ProducerRecord<String, String> record = new ProducerRecord<String, String>("first-topic", "Hello World!");
+
+        // Kafka Producer 만들기
+        KafkaProducer<String, String> producer = new KafkaProducer<String, String>(properties);
+
+        // Consumer한테 데이터 보내기 - 비동기
+        producer.send(record);
+        producer.flush();
+        producer.close();
+    }
+}