kafka-clients
添加依赖
org.apache.kafka
kafka-clients
2.5.0
消费者 Consumer
代码上总体可以分为三部分:
- 消费者的配置消费者的配置在 org.apache.kafka.clients.consumer.ConsumerConfig 类中都有列举包括每个配置项的文档说明
- 创建消费者实例并订阅topic
- 消费消息
代码如下:
// 1. 配置
Properties properties = new Properties();
//bootstrap.servers kafka集群地址 host1:port1,host2:port2 ....
properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "127.0.0.1:9092");
// key.deserializer 消息key序列化方式
properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
// value.deserializer 消息体序列化方式
properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
// group.id 消费组id
properties.put(ConsumerConfig.GROUP_ID_CONFIG, "demo-group");
// enable.auto.commit 设置自动提交offset
properties.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, true);
// auto.offset.reset
properties.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
// 2. 创建消费者实例并订阅topic
KafkaConsumer consumer = new KafkaConsumer<>(properties);
String[] topics = new String[]{"demo-topic"};
consumer.subscribe(Arrays.asList(topics));
// 3. 消费消息
while (true) {
ConsumerRecords records = consumer.poll(Duration.ofMillis(100));
for (ConsumerRecord record : records) {
System.out.println(record);
}
}
生产者 Producer
生产者这块的代码基本上和消费者的结构一样,不同的是,producer 的发消息的部分:
- 生产者的配置在 org.apache.kafka.clients.producer.ProducerConfig 类中也都有列举
- 创建生产者实例
- 发送消息到 topicproducer.send(new ProducerRecord<>("demo-topic", data)) Future.get()
整体代码如下
// 1. 配置
Properties properties = new Properties();
// bootstrap.servers kafka集群地址 host1:port1,host2:port2 ....
properties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "127.0.0.1:9092");
// key.deserializer 消息key序列化方式
properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
// value.deserializer 消息体序列化方式
properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
// 2. 创建生产者实例
KafkaProducer producer = new KafkaProducer<>(properties);
// 3. 发送消息
// 0 异步发送消息
for (int i = 0; i < 10; i++) {
String data = "async :" + i;
// 发送消息
producer.send(new ProducerRecord<>("demo-topic", data));
}
// 1 同步发送消息 调用get()阻塞返回结果
for (int i = 0; i < 10; i++) {
String data = "sync : " + i;
try {
// 发送消息
Future send = producer.send(new ProducerRecord<>("demo-topic", data));
RecordMetadata recordMetadata = send.get();
System.out.println(recordMetadata);
} catch (Exception e) {
e.printStackTrace();
}
}
// 2 异步发送消息 回调callback()
for (int i = 0; i < 10; i++) {
String data = "callback : " + i;
// 发送消息
producer.send(new ProducerRecord<>("demo-topic", data), new Callback() {
@Override
public void onCompletion(RecordMetadata metadata, Exception exception) {
// 发送消息的回调
if (exception != null) {
exception.printStackTrace();
} else {
System.out.println(metadata);
}
}
});
}
producer.close();
整合SpringBoot
添加依赖
org.springframework.boot
spring-boot-starter-parent
2.3.2.RELEASE
....
....
org.springframework.boot
spring-boot-starter
org.springframework.kafka
spring-kafka
org.springframework.boot
spring-boot-starter-test
test
org.springframework.kafka
spring-kafka-test
test
代码
# application.yml
spring:
kafka:
bootstrap-servers: 127.0.0.1:9092
producer:
key-serializer: org.apache.kafka.common.serialization.StringSerializer
value-serializer: org.apache.kafka.common.serialization.StringSerializer
consumer:
key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
value-deserializer: org.apache.kafka.common.serialization.StringDeserializer
group-id: test-group
// 启动类
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
// 消费者
@Component
public class Consumer {
@KafkaListener(topics = { "test-topic" })
public void receiveMessage(String message) {
System.out.println(message);
}
}
// 生产者
@Component
public class Producer {
@Resource
KafkaTemplate kafkaTemplate;
public void sendMessage(String topic, String message) {
kafkaTemplate.send(topic, message);
}
}
// 测试
@RunWith(SpringRunner.class)
@SpringBootTest
public class DemoApplicationTests {
@Autowired
private Producer producer;
@Test
public void send() {
producer.sendMessage("test-topic", "test-message");
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
总结
整合SpringBoot之后的代码还是非常简洁的,不过还是要熟悉原生API,这样才能在实际项目中遇到问题时游刃有余。
来源:https://www.tuicool.com/articles/qInaMnI
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