java - spring boot kafka LocalDateTime

Question

我有一个包含 java.time.LocalDateTime 的基本 POJO:

package foo.bar.asire.api.model;

import java.time.LocalDateTime;

public class Address
{
    private Long id;
    private Integer houseNumber;
    private String address;
    private LocalDateTime created;

    public Address()
    {
        super();
    }

    public Address(Long id, Integer houseNumber, String address, LocalDateTime created)
    {
        super();
        this.id = id;
        this.houseNumber = houseNumber;
        this.address = address;
        this.created = created;
    }

    public Long getId()
    {
        return id;
    }

    public void setId(Long id)
    {
        this.id = id;
    }

    public Integer getHouseNumber()
    {
        return houseNumber;
    }

    public void setHouseNumber(Integer houseNumber)
    {
        this.houseNumber = houseNumber;
    }

    public String getAddress()
    {
        return address;
    }

    public void setAddress(String address)
    {
        this.address = address;
    }

    public LocalDateTime getCreated()
    {
        return created;
    }

    public void setCreated(LocalDateTime created)
    {
        this.created = created;
    }

    @Override
    public String toString()
    {
        return "Address [id=" + id + ", houseNumber=" + houseNumber
                + ", address=" + address + ", created=" + created + "]";
    }

//    @Override
//    public String toString()
//    {
//        return "Address [id=" + id + ", houseNumber=" + houseNumber
//                + ", address=" + address + "]";
//    }


}

如果我删除了 LocalDateTime 对象，我就可以使用来 self 的消费者的以下代码发送/接收和创建地址对象:

package foo.bar.consumer.config;

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

import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.annotation.EnableKafka;
import org.springframework.kafka.config.ConcurrentKafkaListenerContainerFactory;
import org.springframework.kafka.core.ConsumerFactory;
import org.springframework.kafka.core.DefaultKafkaConsumerFactory;
import org.springframework.kafka.support.serializer.JsonDeserializer;

import foo.bar.asire.api.model.Address;

@Configuration
@EnableKafka
public class KafkaConsumerConfig
{
    @Value("${kafka.consumer.bootstrap}")
    private String bootstrapServers;

    @Value("${kafka.consumer.group}")
    private String group;

    @Bean
    public Map<String, Object> consumerConfigs()
    {
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, JsonDeserializer.class);
        props.put(ConsumerConfig.GROUP_ID_CONFIG, group);

        return props;
    }

    @Bean
    public ConsumerFactory<String, Address> consumerFactory()
    {
        return new DefaultKafkaConsumerFactory<>(consumerConfigs(), 
                new StringDeserializer(),
                new JsonDeserializer<>(Address.class));
    }

    @Bean
    public ConcurrentKafkaListenerContainerFactory<String, Address> kafkaListenerContainerFactory()
    {
        ConcurrentKafkaListenerContainerFactory<String, Address> factory = new ConcurrentKafkaListenerContainerFactory<>();
        factory.setConsumerFactory(consumerFactory());

        return factory;
    }
}

这是我的 AddressConsumer @Service:

package foo.bar.consumer.service;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Service;

import foo.bar.asire.api.model.Address;

@Service
public class AddressConsumer
{
    private final Logger log = LoggerFactory.getLogger(this.getClass());

    @KafkaListener(topics = "${kafka.consumer.topic}")
    private void consumeAddress(Address address)
    {
        log.info("received address='{}'", address.toString());
    }
}

但是，当我将原始地址 POJO 与 LocalDateTime 对象一起使用时，出现以下异常:

org.apache.kafka.common.errors.SerializationException: Error deserializing key/value for partition asire-0 at offset 29
Caused by: org.apache.kafka.common.errors.SerializationException: Can't deserialize data [[123, 34, 105, 100, 34, 58, 49, 44, 34, 104, 111, 117, 115, 101, 78, 117, 109, 98, 101, 114, 34, 58, 49, 50, 51, 52, 44, 34, 97, 100, 100, 114, 101, 115, 115, 34, 58, 34, 70, 111, 111, 98, 97, 114, 32, 76, 97, 110, 101, 34, 44, 34, 99, 114, 101, 97, 116, 101, 100, 34, 58, 123, 34, 100, 97, 121, 79, 102, 77, 111, 110, 116, 104, 34, 58, 50, 55, 44, 34, 100, 97, 121, 79, 102, 87, 101, 101, 107, 34, 58, 34, 83, 65, 84, 85, 82, 68, 65, 89, 34, 44, 34, 100, 97, 121, 79, 102, 89, 101, 97, 114, 34, 58, 49, 52, 55, 44, 34, 109, 111, 110, 116, 104, 34, 58, 34, 77, 65, 89, 34, 44, 34, 109, 111, 110, 116, 104, 86, 97, 108, 117, 101, 34, 58, 53, 44, 34, 121, 101, 97, 114, 34, 58, 50, 48, 49, 55, 44, 34, 104, 111, 117, 114, 34, 58, 49, 52, 44, 34, 109, 105, 110, 117, 116, 101, 34, 58, 53, 52, 44, 34, 110, 97, 110, 111, 34, 58, 49, 54, 53, 48, 48, 48, 48, 48, 48, 44, 34, 115, 101, 99, 111, 110, 100, 34, 58, 57, 44, 34, 99, 104, 114, 111, 110, 111, 108, 111, 103, 121, 34, 58, 123, 34, 105, 100, 34, 58, 34, 73, 83, 79, 34, 44, 34, 99, 97, 108, 101, 110, 100, 97, 114, 84, 121, 112, 101, 34, 58, 34, 105, 115, 111, 56, 54, 48, 49, 34, 125, 125, 125]] from topic [asire]
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of java.time.LocalDateTime: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?)
 at [Source: [B@3ad71c11; line: 1, column: 63] (through reference chain: foo.bar.asire.api.model.Address["created"])
    at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:270) ~[jackson-databind-2.8.8.jar:2.8.8]
    at com.fasterxml.jackson.databind.DeserializationContext.instantiationException(DeserializationContext.java:1456) ~[jackson-databind-2.8.8.jar:2.8.8]
    at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1012) ~[jackson-databind-2.8.8.jar:2.8.8]
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1206) ~[jackson-databind-2.8.8.jar:2.8.8]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:314) ~[jackson-databind-2.8.8.jar:2.8.8]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:148) ~[jackson-databind-2.8.8.jar:2.8.8]
    at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:504) ~[jackson-databind-2.8.8.jar:2.8.8]
    at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:104) ~[jackson-databind-2.8.8.jar:2.8.8]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:357) ~[jackson-databind-2.8.8.jar:2.8.8]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:148) ~[jackson-databind-2.8.8.jar:2.8.8]
    at com.fasterxml.jackson.databind.ObjectReader._bindAndClose(ObjectReader.java:1626) ~[jackson-databind-2.8.8.jar:2.8.8]
    at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:1237) ~[jackson-databind-2.8.8.jar:2.8.8]
    at org.springframework.kafka.support.serializer.JsonDeserializer.deserialize(JsonDeserializer.java:86) ~[spring-kafka-1.2.1.RELEASE.jar:na]
    at org.apache.kafka.clients.consumer.internals.Fetcher.parseRecord(Fetcher.java:869) ~[kafka-clients-0.10.2.0.jar:na]
    at org.apache.kafka.clients.consumer.internals.Fetcher.parseCompletedFetch(Fetcher.java:775) ~[kafka-clients-0.10.2.0.jar:na]
    at org.apache.kafka.clients.consumer.internals.Fetcher.fetchedRecords(Fetcher.java:473) ~[kafka-clients-0.10.2.0.jar:na]
    at org.apache.kafka.clients.consumer.KafkaConsumer.pollOnce(KafkaConsumer.java:1062) ~[kafka-clients-0.10.2.0.jar:na]
    at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:995) ~[kafka-clients-0.10.2.0.jar:na]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.run(KafkaMessageListenerContainer.java:556) ~[spring-kafka-1.2.1.RELEASE.jar:na]
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_131]
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_131]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_131]

这是我的 Maven pom.xml 文件，消费者/生产者应用程序基本相同:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>foo.bar</groupId>
    <artifactId>consumer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>consumer</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka</artifactId>
            <version>1.2.1.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>foo.bar</groupId>
            <artifactId>asire-api</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>22.0</version>
        </dependency>

        <!-- Jackson Dependencies --> 
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.datatype</groupId>
            <artifactId>jackson-datatype-jsr310</artifactId>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka-test</artifactId>
            <version>1.2.1.RELEASE</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-core</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-core</artifactId>
            <version>2.7.22</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

这是我的消费者的 application.properties 文件，但我的生产者大致相同:

server.port=8081

spring.jackson.serialization.write_dates_as_timestamps=false

kafka.consumer.bootstrap=localhost:9092
kafka.consumer.topic=asire
kafka.consumer.group=AsireGroup

Answer 1

无论对错，我都能够通过使用以下更改修改原始地址 POJO 来正确执行 JsonSerialization/JsonDeserialization。添加了以下导入:

import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;

添加了以下注释:

@JsonSerialize(using = LocalDateTimeSerializer.class)
@JsonDeserialize(using = LocalDateTimeDeserializer.class)
private LocalDateTime created;