`@KafkaListener`-Version des `spring-consumer` mit Business-Logik

[demos/kafka/training] / src / main / java / de / juplo / kafka / SimpleConsumer.java

diff --git a/src/main/java/de/juplo/kafka/SimpleConsumer.java b/src/main/java/de/juplo/kafka/SimpleConsumer.java
index cea9568..cc7effb 100644 (file)
--- a/src/main/java/de/juplo/kafka/SimpleConsumer.java
+++ b/src/main/java/de/juplo/kafka/SimpleConsumer.java
@@ -1,78 +1,38 @@
 package de.juplo.kafka;
 
-import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
-import org.apache.kafka.clients.consumer.Consumer;
-import org.apache.kafka.clients.consumer.ConsumerRecord;
-import org.apache.kafka.clients.consumer.ConsumerRecords;
-import org.apache.kafka.common.errors.WakeupException;
-
-import java.time.Duration;
-import java.util.Arrays;
-import java.util.concurrent.Callable;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.kafka.annotation.KafkaListener;
+import org.springframework.kafka.support.KafkaHeaders;
+import org.springframework.messaging.handler.annotation.Header;
+import org.springframework.messaging.handler.annotation.Payload;
+import org.springframework.stereotype.Component;
 
 
 @Slf4j
-@RequiredArgsConstructor
-public class SimpleConsumer implements Callable<Integer>
+@Component
+public class SimpleConsumer
 {
-  private final String id;
-  private final String topic;
-  private final Consumer<String, Message> consumer;
-  private final MessageHandler messageHandler;
+  @Value("${spring.kafka.client-id}")
+  private String id;
+  @Autowired
+  private MessageHandler messageHandler;
 
   private long consumed = 0;
 
 
-  @Override
-  public Integer call()
-  {
-    try
-    {
-      log.info("{} - Subscribing to topic {}", id, topic);
-      consumer.subscribe(Arrays.asList(topic));
-
-      while (true)
-      {
-        ConsumerRecords<String, Message> records =
-            consumer.poll(Duration.ofSeconds(1));
-
-        log.info("{} - Received {} messages", id, records.count());
-        for (ConsumerRecord<String, Message> record : records)
-        {
-          handleRecord(
-            record.topic(),
-            record.partition(),
-            record.offset(),
-            record.key(),
-            record.value());
-        }
-      }
-    }
-    catch(WakeupException e)
-    {
-      log.info("{} - Consumer was signaled to finish its work", id);
-      return 0;
-    }
-    catch(Exception e)
-    {
-      log.error("{} - Unexpected error: {}, unsubscribing!", id, e.toString());
-      consumer.unsubscribe();
-      return 1;
-    }
-    finally
-    {
-      log.info("{} - Closing the KafkaConsumer", id);
-      consumer.close();
-      log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
-    }
-  }
-
+  @KafkaListener(topics = "${simple.consumer.topic}")
   private void handleRecord(
+    @Header(KafkaHeaders.RECEIVED_TOPIC)
     String topic,
+    @Header(KafkaHeaders.RECEIVED_PARTITION_ID)
     Integer partition,
+    @Header(KafkaHeaders.OFFSET)
     Long offset,
+    @Header(KafkaHeaders.RECEIVED_MESSAGE_KEY)
     String key,
+    @Payload
     Message value)
   {
     consumed++;