BAEL-4905: Send large messages with Kafka (#10992)

spring-kafka/src/main/java/com/baeldung/spring/kafka/KafkaApplicationLongMessage.java

@@ -0,0 +1,75 @@
+package com.baeldung.spring.kafka;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.kafka.annotation.KafkaListener;
+import org.springframework.kafka.core.KafkaTemplate;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+@SpringBootApplication
+public class KafkaApplicationLongMessage {
+
+    public static void main(String[] args) throws Exception {
+
+        ConfigurableApplicationContext context = SpringApplication.run(KafkaApplicationLongMessage.class, args);
+
+        LongMessageProducer producer = context.getBean(LongMessageProducer.class);
+
+        String fileData = readLongMessage();
+        producer.sendMessage(fileData);
+
+        //Deliberate delay to let listener consume produced message before main thread stops
+        Thread.sleep(5000);
+        context.close();
+    }
+
+    private static String readLongMessage() throws IOException {
+        String data = "";
+
+        //update complete location of large message here
+        data = new String(Files.readAllBytes(Paths.get("RandomTextFile.txt")));
+        return data;
+    }
+
+    @Bean
+    public LongMessageProducer longMessageProducer() {
+        return new LongMessageProducer();
+    }
+
+    @Bean
+    public LongMessageListener longMessageListener() {
+        return new LongMessageListener();
+    }
+
+    public static class LongMessageProducer {
+
+        @Autowired
+        private KafkaTemplate<String, String> kafkaTemplate;
+
+        @Value(value = "${long.message.topic.name}")
+        private String topicName;
+
+        public void sendMessage(String message) {
+            kafkaTemplate.send(topicName, message);
+            System.out.println("Long message Sent");
+        }
+
+    }
+
+    public static class LongMessageListener {
+
+        @KafkaListener(topics = "${long.message.topic.name}", groupId = "longMessage", containerFactory = "longMessageKafkaListenerContainerFactory")
+        public void listenGroupLongMessage(String message) {
+            System.out.println("Received Message in group 'longMessage'");
+        }
+
+    }
+
+}