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java - Kafka Stream with Avro in JAVA , schema.registry.url" 没有默认值

问题描述

我的 Kafka Stream 应用程序有以下配置

    Properties config = new Properties();
    config.put(StreamsConfig.APPLICATION_ID_CONFIG,this.applicaionId);
    config.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG,svrConfig.getBootstrapServers());
    config.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");

    // we disable the cache to demonstrate all the "steps" involved in the transformation - not recommended in prod
    config.put(StreamsConfig.CACHE_MAX_BYTES_BUFFERING_CONFIG, svrConfig.getCacheMaxBytesBufferingConfig());

    // Exactly once processing!!
    config.put(StreamsConfig.PROCESSING_GUARANTEE_CONFIG, StreamsConfig.EXACTLY_ONCE);
    config.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG,SpecificAvroSerde.class);
    config.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG,SpecificAvroSerde.class);
    config.put(AbstractKafkaAvroSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG,"http://localhost:8081");

我收到以下错误：

Exception in thread "main" io.confluent.common.config.ConfigException: Missing required configuration "schema.registry.url" which has no default value.
at io.confluent.common.config.ConfigDef.parse(ConfigDef.java:243)
at io.confluent.common.config.AbstractConfig.<init>(AbstractConfig.java:78)
at io.confluent.kafka.serializers.AbstractKafkaAvroSerDeConfig.<init>(AbstractKafkaAvroSerDeConfig.java:100)
at io.confluent.kafka.serializers.KafkaAvroSerializerConfig.<init>(KafkaAvroSerializerConfig.java:32)
at io.confluent.kafka.serializers.KafkaAvroSerializer.configure(KafkaAvroSerializer.java:48)
at io.confluent.kafka.streams.serdes.avro.SpecificAvroSerializer.configure(SpecificAvroSerializer.java:58)
at io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde.configure(SpecificAvroSerde.java:107)

我试图更换线路

config.put(AbstractKafkaAvroSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG,"http://localhost:8081");

和

config.put("schema.registry.url","http://localhost:8081");

但同样的错误

在准备我的 Stream 应用程序时，我已按照此 url中的说明进行操作。

有什么建议吗？

标签： javaapache-kafkaavroapache-kafka-streamsconfluent-schema-registry

解决方案

如果您有 Avro 格式的键和值，以下几行应该可以为您解决问题，

config.put("key.converter.schema.registry.url", "http://localhost:8081");  
config.put("value.converter.schema.registry.url", "http://localhost:8081");

如果这似乎不起作用，您可以Serdes显式覆盖。例如，如果您有 Avro 密钥：

final Map<String, String> serdeConfig = Collections.singletonMap("schema.registry.url",
                                                                 "http://localhost:8081");
final Serde<GenericRecord> keyGenericAvroSerde = new GenericAvroSerde();
keyGenericAvroSerde.configure(serdeConfig, true); // true for record keys
final Serde<GenericRecord> valueGenericAvroSerde = new GenericAvroSerde();
valueGenericAvroSerde.configure(serdeConfig, false); // false for record values

StreamsBuilder builder = new StreamsBuilder();
KStream<GenericRecord, GenericRecord> textLines =
builder.stream(keyGenericAvroSerde, valueGenericAvroSerde, "my-avro-topic");
// Do whatever you like

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