kafka 自定义Interceptor（通过拦截器对消息进行定制化处理）

文章目录

1. 说明
- 1.1 configure(configs)
- 1.2 onSend(ProducerRecord)
- 1.3 onAcknowledgement(RecordMetadata, Exception)
- 1.4 close
2. 案例

1. 说明

producer生成消息时，interceptor使得用户在消息发送前以及producer回调逻辑触发前对消息做定制化处理。producer允许用户通过配置interceptor.classes参数指定多个interceptor按序作用于同一条消息从而形成一个拦截链(interceptor chain)。Intercetpor的实现接口是org.apache.kafka.clients.producer.ProducerInterceptor

1.1 configure(configs)

可获取配置信息，初始化调用一次

1.2 onSend(ProducerRecord)

方法会运行在用户主线程中，封装进org.apache.kafka.clients.producer.KafkaProducer#send(ProducerRecord, Callback)，确保在消息被序列化以及计算分区前调用。（最好不要修改消息所属的topic和分区）

1.3 onAcknowledgement(RecordMetadata, Exception)

方法会在消息从RecordAccumulator成功发送到Kafka Broker之后，或者在发送过程中失败时调用，即在producer回调逻辑触发之前调用。（不要添加复杂逻辑，否则会拖慢producer的消息发送效率）

1.4 close

关闭拦截器，执行资源清理工作

注：producer将按照指定顺序调用拦截器，并仅捕获每个interceptor可能抛出的异常记录到错误日志中而非在向上传递。

2. 案例

生成拦截链。第一个interceptor会在消息发送前将时间戳信息加到消息value的最前部；第二个interceptor会在消息发送后更新成功发送消息数或失败发送消息数到控制台

拦截器一：

import org.apache.kafka.clients.producer.ProducerInterceptor;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;import java.util.Map;public class TimeInterceptor implements ProducerInterceptor<String, String> {@Overridepublic void configure(Map<String, ?> configs) {}@Overridepublic ProducerRecord<String, String> onSend(ProducerRecord<String, String> record) {return new ProducerRecord<String, String>(record.topic(), record.partition(), record.key(), System.currentTimeMillis() + "----" + record.value());}@Overridepublic void onAcknowledgement(RecordMetadata metadata, Exception exception) {}@Overridepublic void close() {}}

拦截器二：

import org.apache.kafka.clients.producer.ProducerInterceptor;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;import java.util.Map;public class CounterInterceptor implements ProducerInterceptor<String, String> {private int success;private int error;@Overridepublic ProducerRecord<String, String> onSend(ProducerRecord<String, String> record) {return record;}@Overridepublic void onAcknowledgement(RecordMetadata metadata, Exception exception) {if (metadata != null) {success++;} else {error++;}}@Overridepublic void close() {System.out.println("success:" + success);System.out.println("error:" + error);}@Overridepublic void configure(Map<String, ?> configs) {}
}

生产者：

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;import java.util.ArrayList;
import java.util.Properties;public class InterceptorProducer {public static void main(String[] args) throws InterruptedException {Properties props = new Properties();props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.0.23:29092,192.168.0.114:29092,192.168.0.110:29092");//ack应答级别props.put(ProducerConfig.ACKS_CONFIG, "all");//重试次数props.put("retries", 1);//批次大小props.put("batch.size", 16384);//等待时间props.put("linger.ms", 1);//RecordAccumulator缓冲区大小props.put("buffer.memory", 33554432);// key value 序列化props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");/*添加拦截器链*/ArrayList<String> classes = new ArrayList<>();classes.add("com.cz.kafka.interceptor.TimeInterceptor");classes.add("com.cz.kafka.interceptor.CounterInterceptor");props.put(ProducerConfig.INTERCEPTOR_CLASSES_CONFIG, classes);//创建生产者KafkaProducer<String, String> producer = new KafkaProducer<>(props);//发送数据for (int i = 0; i < 10; i++) {producer.send(new ProducerRecord<>("charges", i + ",female,25.84,0,no,northwest,28923.13692"));}//关闭producer.close();}
}