尝试在Kafka中创建分区时的NoClassDefoundError

Question

我有以下代码：

  public KafkaReader(KafkaConsumer<Long, byte[]> consumer, String topic) {
    this.consumer = consumer;
    this.topicPartition = new TopicPartition(topic, ((consumer.partitionsFor(topic).get(0)).partition()));
    consumer.assign(Collections.singleton(topicPartition));
}

java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/JsonNode

at org.apache.kafka.common.requests.MetadataRequest$Builder.<clinit>(MetadataRequest.java:36)
at org.apache.kafka.clients.consumer.KafkaConsumer.partitionsFor(KafkaConsumer.java:1962)
at org.apache.kafka.clients.consumer.KafkaConsumer.partitionsFor(KafkaConsumer.java:1930)
at data.KafkaReader.<init>(KafkaReader.java:20)
at data.KafkaReaderTest.playground(KafkaReaderTest.java:12)

...原因：java.lang.ClassNotFoundException：com.fasterxml.jackson.databind.jsonNode在java.base/jdk.internal.loader.builtInclassLoader.LoadClass（builtInclassLoader.java:581)在java.base/jdk.internal.loader.classLoader.$AppClassLoader.LoadClass（classLoader.java:178)在java.base/java.lang.ClassLoader.LoadClass（

在pom.xml中，我定义了以下依赖项：

   <dependencies>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
        <version>${junit.jupiter.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.hamcrest</groupId>
        <artifactId>hamcrest-all</artifactId>
        <version>1.3</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>commons-cli</groupId>
        <artifactId>commons-cli</artifactId>
        <version>1.4</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.12</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.kafka</groupId>
        <artifactId>kafka-clients</artifactId>
        <version>2.6.0</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.7.25</version>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.17</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.8.10</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-annotations</artifactId>
        <version>2.8.10</version>
    </dependency>
</dependencies>

我所能找到的建议是将jackson-annotations和-core添加到maven依赖项中，但这没有帮助。

Answer 1

这是客户端2.6版本中的一个错误：https://issues.apache.org/jira/browse/kafka-10378

我建议在2.6.1或2.7发布之前坚持2.5客户端。除非有一个关键的2.6特性是你不能没有的，然后建议包含你自己的依赖是一个健全的。