Kafka 中使用 Avro 序列化框架(一):使用传统的 avro API 自定义序列化类和反序列化类

释放双眼,带上耳机,听听看~!

关于 avro 的 maven 工程的搭建以及 avro 的入门知识,可以参考: Apache Avro 入门

1. 定义 schema 文件,并编译 maven 工程生成实体类

schema 文件名称为:stock.avsc,内容如下:


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2{
3    "namespace": "com.bonc.rdpe.kafka110.beans",
4    "type": "record",
5    "name": "Stock",
6    "fields": [
7        {"name": "stockCode", "type": "string"},
8        {"name": "stockName",  "type": "string"},
9        {"name": "tradeTime", "type": "long"},
10        {"name": "preClosePrice", "type": "float"},
11        {"name": "openPrice", "type": "float"},
12        {"name": "currentPrice", "type": "float"},
13        {"name": "highPrice", "type": "float"},
14        {"name": "lowPrice", "type": "float"}
15    ]
16}
17

编译 maven 工程生成实体类:

2. 自定义序列化类和反序列化类

(1) 序列化类


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2package com.bonc.rdpe.kafka110.serializer;
3
4import java.io.ByteArrayOutputStream;
5import java.io.IOException;
6import java.util.Map;
7
8import org.apache.avro.io.BinaryEncoder;
9import org.apache.avro.io.DatumWriter;
10import org.apache.avro.io.EncoderFactory;
11import org.apache.avro.specific.SpecificDatumWriter;
12import org.apache.kafka.common.errors.SerializationException;
13import org.apache.kafka.common.serialization.Serializer;
14
15import com.bonc.rdpe.kafka110.beans.Stock;
16
17/**
18 * @Title AvroSerializer.java
19 * @Description 使用传统的 Avro API 自定义序列化类
20 * @Author YangYunhe
21 * @Date 2018-06-21 16:40:35
22 */
23public class AvroSerializer implements Serializer<Stock> {
24
25    @Override
26    public void close() {}
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28    @Override
29    public void configure(Map<String, ?> arg0, boolean arg1) {}
30
31    @Override
32    public byte[] serialize(String topic, Stock data) {
33        if(data == null) {
34            return null;
35        }
36        DatumWriter<Stock> writer = new SpecificDatumWriter<>(data.getSchema());
37        ByteArrayOutputStream out = new ByteArrayOutputStream();
38        BinaryEncoder encoder = EncoderFactory.get().directBinaryEncoder(out, null);
39        try {
40            writer.write(data, encoder);
41        }catch (IOException e) {
42            throw new SerializationException(e.getMessage());
43        }
44        return out.toByteArray();
45    }
46
47}
48

(2) 反序列化类


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1
2package com.bonc.rdpe.kafka110.deserializer;
3
4import java.io.ByteArrayInputStream;
5import java.io.IOException;
6import java.util.Map;
7
8import org.apache.avro.io.BinaryDecoder;
9import org.apache.avro.io.DatumReader;
10import org.apache.avro.io.DecoderFactory;
11import org.apache.avro.specific.SpecificDatumReader;
12import org.apache.kafka.common.serialization.Deserializer;
13
14import com.bonc.rdpe.kafka110.beans.Stock;
15
16/**
17 * @Title AvroDeserializer.java
18 * @Description 使用传统的 Avro API 自定义反序列类
19 * @Author YangYunhe
20 * @Date 2018-06-21 17:19:40
21 */
22public class AvroDeserializer implements Deserializer<Stock> {
23
24    @Override
25    public void close() {}
26
27    @Override
28    public void configure(Map<String, ?> arg0, boolean arg1) {}
29
30    @Override
31    public Stock deserialize(String topic, byte[] data) {
32        if(data == null) {
33            return null;
34        }
35        Stock stock = new Stock();
36        ByteArrayInputStream in = new ByteArrayInputStream(data);
37        DatumReader<Stock> userDatumReader = new SpecificDatumReader<>(stock.getSchema());
38        BinaryDecoder decoder = DecoderFactory.get().directBinaryDecoder(in, null);
39        try {
40            stock = userDatumReader.read(null, decoder);
41        } catch (IOException e) {
42            e.printStackTrace();
43        }
44        return stock;
45    }
46}
47

3. KafkaProducer使用自定义的序列化类发送消息


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2package com.bonc.rdpe.kafka110.producer;
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4import java.util.Properties;
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6import org.apache.kafka.clients.producer.KafkaProducer;
7import org.apache.kafka.clients.producer.Producer;
8import org.apache.kafka.clients.producer.ProducerRecord;
9import org.apache.kafka.clients.producer.RecordMetadata;
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11import com.bonc.rdpe.kafka110.beans.Stock;
12
13/**
14 * @Title TraditionalAvroProducer.java
15 * @Description Kafka Producer 发送avro序列化后的Stock对象
16 * @Author YangYunhe
17 * @Date 2018-06-21 17:41:59
18 */
19public class TraditionalAvroProducer {
20    
21    public static void main(String[] args) throws Exception {
22        
23        Stock[] stocks = new Stock[100];
24        for(int i = 0; i < 100; i++) {
25            stocks[i] = new Stock();
26            stocks[i].setStockCode(String.valueOf(i));
27            stocks[i].setStockName("stock" + i);
28            stocks[i].setTradeTime(System.currentTimeMillis());
29            stocks[i].setPreClosePrice(100.0F);
30            stocks[i].setOpenPrice(88.8F);
31            stocks[i].setCurrentPrice(120.5F);
32            stocks[i].setHighPrice(300.0F);
33            stocks[i].setLowPrice(12.4F);
34        }
35        
36        Properties props = new Properties();
37        props.put("bootstrap.servers", "192.168.42.89:9092,192.168.42.89:9093,192.168.42.89:9094");
38        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
39        // 设置序列化类为自定义的 avro 序列化类
40        props.put("value.serializer", "com.bonc.rdpe.kafka110.serializer.AvroSerializer");
41
42        Producer<String, Stock> producer = new KafkaProducer<>(props);
43        
44        for(Stock stock : stocks) {
45            ProducerRecord<String, Stock> record = new ProducerRecord<>("dev3-yangyunhe-topic001", stock);
46            RecordMetadata metadata = producer.send(record).get();
47            StringBuilder sb = new StringBuilder();
48            sb.append("stock: ").append(stock.toString()).append(" has been sent successfully!").append("\n")
49                .append("send to partition ").append(metadata.partition())
50                .append(", offset = ").append(metadata.offset());
51            System.out.println(sb.toString());
52            Thread.sleep(100);
53        }
54        
55        producer.close();
56    }
57}
58

4. KafkaConsumer使用自定义的反序列化类接收消息


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2package com.bonc.rdpe.kafka110.consumer;
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4import java.util.Collections;
5import java.util.Properties;
6
7import org.apache.kafka.clients.consumer.ConsumerRecord;
8import org.apache.kafka.clients.consumer.ConsumerRecords;
9import org.apache.kafka.clients.consumer.KafkaConsumer;
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11import com.bonc.rdpe.kafka110.beans.Stock;
12
13/**
14 * @Title TraditionalAvroConsumer.java
15 * @Description Kafka Consumer 解析avro序列化后的Stock对象
16 * @Author YangYunhe
17 * @Date 2018-06-21 17:43:03
18 */
19public class TraditionalAvroConsumer {
20    
21    public static void main(String[] args) {
22        
23        Properties props = new Properties();
24        props.put("bootstrap.servers", "192.168.42.89:9092,192.168.42.89:9093,192.168.42.89:9094");
25        props.put("group.id", "dev3-yangyunhe-group001");
26        props.put("key.deserializer","org.apache.kafka.common.serialization.StringDeserializer");
27        // 设置反序列化类为自定义的avro反序列化类
28        props.put("value.deserializer","com.bonc.rdpe.kafka110.deserializer.AvroDeserializer");
29        KafkaConsumer<String, Stock> consumer = new KafkaConsumer<>(props);
30        
31        consumer.subscribe(Collections.singletonList("dev3-yangyunhe-topic001"));
32        
33        try {
34            while(true) {
35                ConsumerRecords<String, Stock> records = consumer.poll(100);
36                for(ConsumerRecord<String, Stock> record : records) {
37                    Stock stock = record.value();
38                    System.out.println(stock.toString());
39                }
40            }
41        }finally {
42            consumer.close();
43        }
44    }
45}
46

5. 测试结果

运行生产者代码后控制台输出:


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2stock: {"stockCode": "0", "stockName": "stock0", "tradeTime": 1529631848353, "preClosePrice": 100.0, "openPrice": 88.8, "currentPrice": 120.5, "highPrice": 300.0, "lowPrice": 12.4} has been sent successfully!
3send to partition 0, offset = 552
4stock: {"stockCode": "1", "stockName": "stock1", "tradeTime": 1529631848353, "preClosePrice": 100.0, "openPrice": 88.8, "currentPrice": 120.5, "highPrice": 300.0, "lowPrice": 12.4} has been sent successfully!
5send to partition 2, offset = 551
6stock: {"stockCode": "2", "stockName": "stock2", "tradeTime": 1529631848353, "preClosePrice": 100.0, "openPrice": 88.8, "currentPrice": 120.5, "highPrice": 300.0, "lowPrice": 12.4} has been sent successfully!
7send to partition 1, offset = 551
8stock: {"stockCode": "3", "stockName": "stock3", "tradeTime": 1529631848353, "preClosePrice": 100.0, "openPrice": 88.8, "currentPrice": 120.5, "highPrice": 300.0, "lowPrice": 12.4} has been sent successfully!
9send to partition 0, offset = 553
10stock: {"stockCode": "4", "stockName": "stock4", "tradeTime": 1529631848353, "preClosePrice": 100.0, "openPrice": 88.8, "currentPrice": 120.5, "highPrice": 300.0, "lowPrice": 12.4} has been sent successfully!
11send to partition 2, offset = 552
12
13......
14

运行消费者代码后控制台输出:


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2{"stockCode": "0", "stockName": "stock0", "tradeTime": 1529631848353, "preClosePrice": 100.0, "openPrice": 88.8, "currentPrice": 120.5, "highPrice": 300.0, "lowPrice": 12.4}
3{"stockCode": "1", "stockName": "stock1", "tradeTime": 1529631848353, "preClosePrice": 100.0, "openPrice": 88.8, "currentPrice": 120.5, "highPrice": 300.0, "lowPrice": 12.4}
4{"stockCode": "2", "stockName": "stock2", "tradeTime": 1529631848353, "preClosePrice": 100.0, "openPrice": 88.8, "currentPrice": 120.5, "highPrice": 300.0, "lowPrice": 12.4}
5{"stockCode": "3", "stockName": "stock3", "tradeTime": 1529631848353, "preClosePrice": 100.0, "openPrice": 88.8, "currentPrice": 120.5, "highPrice": 300.0, "lowPrice": 12.4}
6{"stockCode": "4", "stockName": "stock4", "tradeTime": 1529631848353, "preClosePrice": 100.0, "openPrice": 88.8, "currentPrice": 120.5, "highPrice": 300.0, "lowPrice": 12.4}
7
8......
9

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