关于kafka-clients JAVA API的基本使用

首先老规矩, 引入maven依赖

 <dependency>
     <groupId>org.apache.kafka</groupId>
     <artifactId>kafka-clients</artifactId>
     <version>1.0.0</version>
 </dependency>

关于kafka-clients的消息生产者:

 @Slf4j
 public class KafkaProducerClient {

     public static void pushMsg(String msg) throws Exception {
         Properties props = new Properties();
         props.put("bootstrap.servers", KafkaConstant.KAFKA_SERVER_ADDRESS);
         props.put("acks", "0");
         props.put("retries", 0);
         props.put("batch.size", 16384);
         props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
         props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
         Producer producer = new KafkaProducer(props);
         ProducerRecord<String, String> record = new ProducerRecord<>(KafkaConstant.KAFKA_TOPIC_NAME, 0, "123", msg);
         producer.send(record, new Callback() {
             @Override
             public void onCompletion(RecordMetadata metadata, Exception e) {
                 if (e != null) {
                     e.printStackTrace();
                 }
                 log.info("pushMsg of msg: {}, metadata: {}", msg, metadata);
             }
         });
         producer.close();
     }

 }

关于kafka-clients的消息消费者

 @Slf4j
 public class KafkaConsumerClient extends Thread {

     private KafkaConsumerClient() {
     }

     /**
      * 初始化consumer
      */
     public void initKafkaConsumer () {
         log.info("init Kafka Consumer");
         new KafkaConsumerClient().start();
     }

     @Override
     public void run() {
         Properties props = new Properties();

         props.put("bootstrap.servers", KafkaConstant.KAFKA_SERVER_ADDRESS);
         props.put("group.id", "1");
         props.put("enable.auto.commit", "true");
         props.put("auto.commit.interval.ms", "1000");
         props.put("session.timeout.ms", "30000");
         props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
         props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");

         Consumer<String, String> consumer = new KafkaConsumer<>(props);
         consumer.subscribe(Arrays.asList(KafkaConstant.KAFKA_TOPIC_NAME));
         consumer.seekToBeginning(new ArrayList<>());

         // ===== 拿到所有的topic ===== //
         Map<String, List<PartitionInfo>> listTopics = consumer.listTopics();
         Set<Map.Entry<String, List<PartitionInfo>>> entries = listTopics.entrySet();

         while (true) {
             ConsumerRecords<String, String> records = consumer.poll(1000 * 60);
             for(ConsumerRecord<String, String> record : records) {
                 System.out.println("[fetched from partition " + record.partition() + ", offset: " + record.offset() + ", message: " + record.value() + "]");
             }
         }
     }
 }

我们需要在项目启动的时候将消费者consumer启动起来

 <bean id="initKafkaConsumer" class="com.dywl.zhoushan.kafka.KafkaConsumerClient" init-method="initKafkaConsumer"></bean>

然后调用生产者producer时, 消费者consumer就能拿到消息

如:

 @Override
 public void pushMsgById(Long id) throws Exception {
     User user = new User();
     user.setId(id);
     user.setUsername("test11111111");
     user.setPassword("test22222222");
     String str = JsonUtil.toCompactJsonString(user);
     log.info("pushMsgById is user: {}", str);
     KafkaProducerClient.pushMsg(str);
 }

得到结果: