update spring-kafka project with support for multiple partitions and JSON serializer (#1472)

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

@@ -10,21 +10,61 @@ 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.annotation.TopicPartition;
 import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.kafka.support.KafkaHeaders;
+import org.springframework.messaging.handler.annotation.Header;
+import org.springframework.messaging.handler.annotation.Payload;
 
 @SpringBootApplication
 public class KafkaApplication {
 
     public static void main(String[] args) throws Exception {
+
         ConfigurableApplicationContext context = SpringApplication.run(KafkaApplication.class, args);
+
         MessageProducer producer = context.getBean(MessageProducer.class);
-        producer.sendMessage("Hello, World!");
-
         MessageListener listener = context.getBean(MessageListener.class);
-        listener.latch.await(20, TimeUnit.SECONDS);
-        Thread.sleep(60000);
-        context.close();
+        /*
+         * Sending a Hello World message to topic 'baeldung'. 
+         * Must be recieved by both listeners with group foo
+         * and bar with containerFactory fooKafkaListenerContainerFactory
+         * and barKafkaListenerContainerFactory respectively.
+         * It will also be recieved by the listener with
+         * headersKafkaListenerContainerFactory as container factory
+         */
+        producer.sendMessage("Hello, World!");
+        listener.latch.await(10, TimeUnit.SECONDS);
 
+        /*
+         * Sending message to a topic with 5 partition,
+         * each message to a different partition. But as per
+         * listener configuration, only the messages from
+         * partition 0 and 3 will be consumed.
+         */
+        for (int i = 0; i < 5; i++) {
+            producer.sendMessageToPartion("Hello To Partioned Topic!", i);
+        }
+        listener.partitionLatch.await(10, TimeUnit.SECONDS);
+
+        /*
+         * Sending message to 'filtered' topic. As per listener
+         * configuration,  all messages with char sequence
+         * 'World' will be discarded.
+         */
+        producer.sendMessageToFiltered("Hello Baeldung!");
+        producer.sendMessageToFiltered("Hello World!");
+        listener.filterLatch.await(10, TimeUnit.SECONDS);
+
+        /*
+         * Sending message to 'greeting' topic. This will send
+         * and recieved a java object with the help of 
+         * greetingKafkaListenerContainerFactory.
+         */
+        producer.sendGreetingMessage(new Greeting("Greetings", "World!"));
+        listener.greetingLatch.await(10, TimeUnit.SECONDS);
+
+        context.close();
     }
 
     @Bean
@@ -42,18 +82,47 @@ public class KafkaApplication {
         @Autowired
         private KafkaTemplate<String, String> kafkaTemplate;
 
+        @Autowired
+        private KafkaTemplate<String, Greeting> greetingKafkaTemplate;
+
         @Value(value = "${message.topic.name}")
         private String topicName;
 
+        @Value(value = "${partitioned.topic.name}")
+        private String partionedTopicName;
+
+        @Value(value = "${filtered.topic.name}")
+        private String filteredTopicName;
+
+        @Value(value = "${greeting.topic.name}")
+        private String greetingTopicName;
+
         public void sendMessage(String message) {
             kafkaTemplate.send(topicName, message);
         }
 
+        public void sendMessageToPartion(String message, int partition) {
+            kafkaTemplate.send(partionedTopicName, partition, message);
+        }
+
+        public void sendMessageToFiltered(String message) {
+            kafkaTemplate.send(filteredTopicName, message);
+        }
+
+        public void sendGreetingMessage(Greeting greeting) {
+            greetingKafkaTemplate.send(greetingTopicName, greeting);
+        }
     }
 
     public static class MessageListener {
 
-        private CountDownLatch latch = new CountDownLatch(2);
+        private CountDownLatch latch = new CountDownLatch(3);
+
+        private CountDownLatch partitionLatch = new CountDownLatch(2);
+
+        private CountDownLatch filterLatch = new CountDownLatch(2);
+
+        private CountDownLatch greetingLatch = new CountDownLatch(1);
 
         @KafkaListener(topics = "${message.topic.name}", group = "foo", containerFactory = "fooKafkaListenerContainerFactory")
         public void listenGroupFoo(String message) {
@@ -67,6 +136,30 @@ public class KafkaApplication {
             latch.countDown();
         }
 
+        @KafkaListener(topics = "${message.topic.name}", containerFactory = "headersKafkaListenerContainerFactory")
+        public void listenWithHeaders(@Payload String message, @Header(KafkaHeaders.RECEIVED_PARTITION_ID) int partition) {
+            System.out.println("Received Messasge: " + message + " from partition: " + partition);
+            latch.countDown();
+        }
+
+        @KafkaListener(topicPartitions = @TopicPartition(topic = "${partitioned.topic.name}", partitions = { "0", "3" }))
+        public void listenToParition(@Payload String message, @Header(KafkaHeaders.RECEIVED_PARTITION_ID) int partition) {
+            System.out.println("Received Message: " + message + " from partition: " + partition);
+            this.partitionLatch.countDown();
+        }
+
+        @KafkaListener(topics = "${filtered.topic.name}", containerFactory = "filterKafkaListenerContainerFactory")
+        public void listenWithFilter(String message) {
+            System.out.println("Recieved Message in filtered listener: " + message);
+            this.filterLatch.countDown();
+        }
+
+        @KafkaListener(topics = "${greeting.topic.name}", containerFactory = "greetingKafkaListenerContainerFactory")
+        public void greetingListener(Greeting greeting) {
+            System.out.println("Recieved greeting message: " + greeting);
+            this.greetingLatch.countDown();
+        }
+
     }
 
 }