|NO.Z.00023|——————————|BigDataEnd|——|Hadoop&kafka.V08|——|kafka.v08|拦截器剖析.v02|

一、实现ProducerInterceptor接口

### --- 消息实体类：

package cn.yanqi.kafka.demo.entity;

public class User {
    private Integer userId;
    private String username;
    public Integer getUserId() {
        return userId;
    }
    public void setUserId(Integer userId) {
        this.userId = userId;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
}

### --- 自定义序列化器

package cn.yanqi.kafka.demo.serializer;

import cn.yanqi.kafka.demo.entity.User;
import org.apache.kafka.common.errors.SerializationException;
import org.apache.kafka.common.serialization.Serializer;
import java.io.UnsupportedEncodingException;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.util.Map;

public class UserSerializer implements Serializer<User> {
    @Override
    public void configure(Map<String, ?> configs, boolean isKey) {
// do nothing
    }
    @Override
    public byte[] serialize(String topic, User data) {
        try {
// 如果数据是null，则返回null
            if (data == null) {
                return null;
            }
            Integer userId = data.getUserId();
            String username = data.getUsername();
            int length = 0;
            byte[] bytes = null;
            if (null != username) {
                bytes = username.getBytes("utf-8");
                length = bytes.length;
            }
            ByteBuffer buffer = ByteBuffer.allocate(4 + 4 + length);
            buffer.putInt(userId);
            buffer.putInt(length);
            buffer.put(bytes);
            return buffer.array();
        } catch (UnsupportedEncodingException e) {
            throw new SerializationException("序列化数据异常");
        }
    }
    @Override
    public void close() {
// do nothing
    }
}

### --- 自定义分区器

package cn.yanqi.kafka.demo.partitioner;

import org.apache.kafka.clients.producer.Partitioner;
import org.apache.kafka.common.Cluster;
import java.util.Map;
        
public class MyPartitioner implements Partitioner {
    @Override
    public int partition(String topic, Object key, byte[] keyBytes, Object
            value, byte[] valueBytes, Cluster cluster) {
        return 2;
    }
    @Override
    public void close() {
    }
    @Override
    public void configure(Map<String, ?> configs) {
    }
}

二、编程代码实现：test里查看代码实现

### --- 编程代码

package com.yanqi.kafka.test;

import org.apache.kafka.clients.producer.ProducerInterceptor;

public class MyTest {

    public static void main(String[] args) {

        ProducerInterceptor interceptor;

    }

}

三、编程代码实现：

### --- 自定义拦截器1

package com.yanqi.kafka.demo.interceptor;

import org.apache.kafka.clients.producer.ProducerInterceptor;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;
import org.apache.kafka.common.header.Headers;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Map;

public class InterceptorOne implements ProducerInterceptor<Integer, String> {

    private static final Logger LOGGER = LoggerFactory.getLogger(InterceptorOne.class);

    @Override
    public ProducerRecord<Integer, String> onSend(ProducerRecord<Integer, String> record) {
        System.out.println("拦截器1 -- go");


        // 消息发送的时候，经过拦截器，调用该方法

        // 要发送的消息内容
        final String topic = record.topic();
        final Integer partition = record.partition();
        final Integer key = record.key();
        final String value = record.value();
        final Long timestamp = record.timestamp();
        final Headers headers = record.headers();


        // 拦截器拦下来之后根据原来消息创建的新的消息
        // 此处对原消息没有做任何改动
        ProducerRecord<Integer, String> newRecord = new ProducerRecord<Integer, String>(
                topic,
                partition,
                timestamp,
                key,
                value,
                headers
        );
        // 传递新的消息
        return newRecord;
    }

    @Override
    public void onAcknowledgement(RecordMetadata metadata, Exception exception) {
        System.out.println("拦截器1 -- back");
        // 消息确认或异常的时候，调用该方法，该方法中不应实现较重的任务
        // 会影响kafka生产者的性能。
    }

    @Override
    public void close() {

    }

    @Override
    public void configure(Map<String, ?> configs) {
        final Object classContent = configs.get("classContent");
        System.out.println(classContent);
    }
}

### --- 自定义拦截器2

package com.yanqi.kafka.demo.interceptor;

import org.apache.kafka.clients.producer.ProducerInterceptor;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;
import org.apache.kafka.common.header.Headers;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Map;

public class InterceptorTwo implements ProducerInterceptor<Integer, String> {

    private static final Logger LOGGER = LoggerFactory.getLogger(InterceptorTwo.class);

    @Override
    public ProducerRecord<Integer, String> onSend(ProducerRecord<Integer, String> record) {
        System.out.println("拦截器2 -- go");


        // 消息发送的时候，经过拦截器，调用该方法

        // 要发送的消息内容
        final String topic = record.topic();
        final Integer partition = record.partition();
        final Integer key = record.key();
        final String value = record.value();
        final Long timestamp = record.timestamp();
        final Headers headers = record.headers();


        // 拦截器拦下来之后根据原来消息创建的新的消息
        // 此处对原消息没有做任何改动
        ProducerRecord<Integer, String> newRecord = new ProducerRecord<Integer, String>(
                topic,
                partition,
                timestamp,
                key,
                value,
                headers
        );
        // 传递新的消息
        return newRecord;
    }

    @Override
    public void onAcknowledgement(RecordMetadata metadata, Exception exception) {
        System.out.println("拦截器2 -- back");
        // 消息确认或异常的时候，调用该方法，该方法中不应实现较重的任务
        // 会影响kafka生产者的性能。
    }

    @Override
    public void close() {

    }

    @Override
    public void configure(Map<String, ?> configs) {
        final Object classContent = configs.get("classContent");
        System.out.println(classContent);
    }
}

### --- 自定义拦截器3

package com.yanqi.kafka.demo.interceptor;

import org.apache.kafka.clients.producer.ProducerInterceptor;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;
import org.apache.kafka.common.header.Headers;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Map;

public class InterceptorThree implements ProducerInterceptor<Integer, String> {

    private static final Logger LOGGER = LoggerFactory.getLogger(InterceptorThree.class);

    @Override
    public ProducerRecord<Integer, String> onSend(ProducerRecord<Integer, String> record) {
        System.out.println("拦截器3 -- go");


        // 消息发送的时候，经过拦截器，调用该方法

        // 要发送的消息内容
        final String topic = record.topic();
        final Integer partition = record.partition();
        final Integer key = record.key();
        final String value = record.value();
        final Long timestamp = record.timestamp();
        final Headers headers = record.headers();


        // 拦截器拦下来之后根据原来消息创建的新的消息
        // 此处对原消息没有做任何改动
        ProducerRecord<Integer, String> newRecord = new ProducerRecord<Integer, String>(
                topic,
                partition,
                timestamp,
                key,
                value,
                headers
        );
        // 传递新的消息
        return newRecord;
    }

    @Override
    public void onAcknowledgement(RecordMetadata metadata, Exception exception) {
        System.out.println("拦截器3 -- back");
        // 消息确认或异常的时候，调用该方法，该方法中不应实现较重的任务
        // 会影响kafka生产者的性能。
    }

    @Override
    public void close() {

    }

    @Override
    public void configure(Map<String, ?> configs) {
        final Object classContent = configs.get("classContent");
        System.out.println(classContent);
    }
}

### --- 定义消费者

package com.yanqi.kafka.demo.producer;

import org.apache.kafka.clients.producer.*;
import org.apache.kafka.common.serialization.IntegerSerializer;
import org.apache.kafka.common.serialization.StringSerializer;

import java.util.HashMap;
import java.util.Map;

public class MyProducer {
    public static void main(String[] args) {

        Map<String, Object> configs = new HashMap<>();
        configs.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "node1:9092");
        configs.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
        configs.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);

        // 保证等待确认的消息只有设置的这几个。如果设置为1，则只有一个请求在等待响应
        // 此时可以保证发送消息即使在重试的情况下也是有序的。
        configs.put(ProducerConfig.MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION, 1);
//        configs.put("max.in.flight.requests.per.connection", 1);

//        interceptor.classes
        // 如果有多个拦截器，则设置为多个拦截器类的全限定类名，中间用逗号隔开
        configs.put(ProducerConfig.INTERCEPTOR_CLASSES_CONFIG, "com.yanqi.kafka.demo.interceptor.InterceptorOne," +
                "com.yanqi.kafka.demo.interceptor.InterceptorTwo," +
                "com.yanqi.kafka.demo.interceptor.InterceptorThree");


        configs.put("classContent", "this is yanqi's kafka class");

        KafkaProducer<Integer, String> producer = new KafkaProducer<Integer, String>(configs);

        ProducerRecord<Integer, String> record = new ProducerRecord<Integer, String>(
                "tp_inter_01",
                0,
                1001,
                "this is yanqi's 1001 message"
        );

        producer.send(record, new Callback() {
            @Override
            public void onCompletion(RecordMetadata metadata, Exception exception) {
                if (exception == null) {
                    System.out.println(metadata.offset());
                }
            }
        });

        // 关闭生产者
        producer.close();


    }
}

四、编译运行

### --- 创建主题

[root@hadoop ~]# kafka-topics.sh --zookeeper localhost:2181/myKafka --create --topic tp_inter_01 --partitions 4 --replication-factor 1
[root@hadoop ~]# kafka-topics.sh --zookeeper localhost:2181/myKafka --list
tp_inter_01

### --- 开启消费者消费消息

[root@hadoop ~]# kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic tp_inter_01
~~消费消息
 this is yanqi's 1001 message

### --- 编译打印：MyProducer

D:\JAVA\jdk1.8.0_231\bin\java.exe "-javaagent:D:\IntelliJIDEA\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=53127:D:\IntelliJIDEA\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath D:\JAVA\jdk1.8.0_231\jre\lib\charsets.jar;D:\JAVA\jdk1.8.0_231\jre\lib\deploy.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\access-bridge-64.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\cldrdata.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\dnsns.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\jaccess.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\jfxrt.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\localedata.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\nashorn.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunec.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunjce_provider.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunmscapi.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunpkcs11.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\zipfs.jar;D:\JAVA\jdk1.8.0_231\jre\lib\javaws.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jce.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jfr.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jfxswt.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jsse.jar;D:\JAVA\jdk1.8.0_231\jre\lib\management-agent.jar;D:\JAVA\jdk1.8.0_231\jre\lib\plugin.jar;D:\JAVA\jdk1.8.0_231\jre\lib\resources.jar;D:\JAVA\jdk1.8.0_231\jre\lib\rt.jar;E:\NO.Z.10000——javaproject\NO.Z.00002.Hadoop\kafka_demo\demo-07-kafka-customInterceptor\target\classes;C:\Users\Administrator\.m2\repository\org\apache\kafka\kafka-clients\1.0.2\kafka-clients-1.0.2.jar;C:\Users\Administrator\.m2\repository\org\lz4\lz4-java\1.4\lz4-java-1.4.jar;C:\Users\Administrator\.m2\repository\org\xerial\snappy\snappy-java\1.1.4\snappy-java-1.1.4.jar;C:\Users\Administrator\.m2\repository\org\slf4j\slf4j-api\1.7.25\slf4j-api-1.7.25.jar com.yanqi.kafka.demo.producer.MyProducer
this is yanqi's kafka class
this is yanqi's kafka class
this is yanqi's kafka class
拦截器1 -- go
拦截器2 -- go
拦截器3 -- go
拦截器1 -- back
拦截器2 -- back
拦截器3 -- back
0

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Walter Savage Landor:strove with none,for none was worth my strife.Nature I loved and, next to Nature, Art:I warm'd both hands before the fire of life.It sinks, and I am ready to depart

                                                                                                                                                   ——W.S.Landor

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