Добавил key

src/main/java/ru/ldeloff/demokafkastream/DemoKafkaStreamApplication.java

@@ -1,26 +1,17 @@
 package ru.ldeloff.demokafkastream;
 
 
-import com.fasterxml.jackson.core.JsonParser;
-import com.fasterxml.jackson.databind.ObjectMapper;
-import lombok.*;
-import org.apache.kafka.common.network.Mode;
-import org.apache.logging.log4j.CloseableThreadContext;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.cloud.stream.function.StreamBridge;
-import org.springframework.context.MessageSource;
 import org.springframework.context.annotation.Bean;
+import org.springframework.kafka.support.KafkaHeaders;
 import org.springframework.messaging.Message;
+import org.springframework.messaging.support.MessageBuilder;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
-import org.apache.kafka.common.serialization.StringSerializer;
 
-import java.io.DataInput;
-import java.io.IOException;
-import java.io.Serializable;
-import java.util.Objects;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 
@@ -41,29 +32,32 @@ public class DemoKafkaStreamApplication {
     // Консьюмер
     @Bean
     public Consumer<Model> consumerAuto1() {
-        return message -> {;
+        return message -> {
     //        System.out.println("Consume auto 1: " + message);
         };
     }
 
     // Продюсер (сам периодически отправляет сообщения)
     @Bean
-    public Supplier<Model> producerAuto1() {
+    public Supplier<Message<Model>> producerAuto1() {
         return () -> {
             Model message = new Model(++i);
     //        System.out.println("Produce auto 1:" + message);
-            return message;
+            return MessageBuilder.withPayload(message)
+                    .setHeader(KafkaHeaders.KEY, String.valueOf(message.getId()))
+                    .build();
         };
     }
 
-
-
     // Вручную отправим сообщение
     @GetMapping(value = "/test1")
     public String test1() {
         Model message = new Model(++i);
         System.out.println("Produce manual (kafka 1): " + message);
-        streamBridge.send("producerManual1-out-0", message);
+        streamBridge.send("producerManual1-out-0",
+                MessageBuilder.withPayload(message)
+                        .setHeader(KafkaHeaders.KEY, String.valueOf(message.getId()))
+                        .build());
         return "test OK";
     }
 

src/main/resources/application.yml

@@ -44,6 +44,8 @@ spring:
                 stream:
                   kafka:
                     binder:
+                      producer-properties:
+                        key.serializer: "org.apache.kafka.common.serialization.StringSerializer"
                       brokers:
                         - 192.168.10.101:29092