序列化Avro消息时出错-Kafka Schema Registry

我正在创建一个avro类，其中包含一个字符串和一个地图字段。我可以通过maven生成avro类，并且能够在localhost：8081中创建注册表

.avsc文件：

  {
"type":"record",
"name":"AvroClass",
"namespace":"belliPack.avro",
"fields":[
{
"name":"title",
"type":"string"
},
{
"name":"map",
"type": {"type": "map", "values": "double"}
}
]
}

架构注册表返回以下内容：$ curl -X GET http：// localhost：8081 / subjects / teste1-value / versions / 1

{"subject":"teste1-value","version":1,"id":42,"schema":"{"type":"record","name":"AvroClass","namespace":"belliPack.avro","fields":[{"name":"title","type":"string"},{"name":"map","type":{"type":"map","values":"double"}}]}"}

我的卡夫卡制作人班是：

public KafkaProducer<String, AvroClass> createKafkaProducer() {
    String bootstrapServer = "127.0.0.1:9092";
    String schemaRegistryURL = "127.0.0.1:8081";

    //create Producer properties
    Properties properties = new Properties();
    //kafka documentation>producer configs
    properties.setProperty(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServer);
    properties.setProperty(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
    properties.setProperty(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, KafkaAvroSerializer.class.getName());
    properties.setProperty(AbstractKafkaAvroSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG,schemaRegistryURL);

    //create producer
    KafkaProducer<String, AvroClass> producer = new KafkaProducer<>(properties);
    return producer;
}

但是在运行我的Kafka Producer时出现以下错误：

    Exception in thread "Thread-1" Exception in thread "Thread-3" org.apache.kafka.common.errors.SerializationException: Error serializing Avro message
Caused by: java.net.MalformedURLException: no protocol: 127.0.0.1:8081/subjects/teste1-value/versions
at java.base/java.net.URL.(URL.java:644)
at java.base/java.net.URL.(URL.java:540)
at java.base/java.net.URL.(URL.java:487)
at io.confluent.kafka.schemaregistry.client.rest.RestService.sendHttpRequest(RestService.java:175)
at io.confluent.kafka.schemaregistry.client.rest.RestService.httpRequest(RestService.java:256)
at io.confluent.kafka.schemaregistry.client.rest.RestService.registerSchema(RestService.java:356)
at io.confluent.kafka.schemaregistry.client.rest.RestService.registerSchema(RestService.java:348)
at io.confluent.kafka.schemaregistry.client.rest.RestService.registerSchema(RestService.java:334)
at io.confluent.kafka.schemaregistry.client.CachedSchemaRegistryClient.registerAndGetId(CachedSchemaRegistryClient.java:168)
at io.confluent.kafka.schemaregistry.client.CachedSchemaRegistryClient.register(CachedSchemaRegistryClient.java:222)
at io.confluent.kafka.schemaregistry.client.CachedSchemaRegistryClient.register(CachedSchemaRegistryClient.java:198)
at io.confluent.kafka.serializers.AbstractKafkaAvroSerializer.serializeImpl(AbstractKafkaAvroSerializer.java:70)
at io.confluent.kafka.serializers.KafkaAvroSerializer.serialize(KafkaAvroSerializer.java:53)
at org.apache.kafka.common.serialization.Serializer.serialize(Serializer.java:62)
at org.apache.kafka.clients.producer.KafkaProducer.doSend(KafkaProducer.java:903)
at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:865)
at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:752)
at belliPack.Kafka.Kafka_Producer.sendData(Kafka_Producer.java:32)
at belliPack.OPC.ExtractNodeValues.run(ExtractNodeValues.java:82)
at java.base/java.lang.Thread.run(Thread.java:834)
org.apache.kafka.common.errors.SerializationException: Error serializing Avro message
Caused by: java.net.MalformedURLException: no protocol: 127.0.0.1:8081/subjects/teste1-value/versions
at java.base/java.net.URL.(URL.java:644)
at java.base/java.net.URL.(URL.java:540)
at java.base/java.net.URL.(URL.java:487)
at io.confluent.kafka.schemaregistry.client.rest.RestService.sendHttpRequest(RestService.java:175)
at io.confluent.kafka.schemaregistry.client.rest.RestService.httpRequest(RestService.java:256)
at io.confluent.kafka.schemaregistry.client.rest.RestService.registerSchema(RestService.java:356)
at io.confluent.kafka.schemaregistry.client.rest.RestService.registerSchema(RestService.java:348)
at io.confluent.kafka.schemaregistry.client.rest.RestService.registerSchema(RestService.java:334)
at io.confluent.kafka.schemaregistry.client.CachedSchemaRegistryClient.registerAndGetId(CachedSchemaRegistryClient.java:168)
at io.confluent.kafka.schemaregistry.client.CachedSchemaRegistryClient.register(CachedSchemaRegistryClient.java:222)
at io.confluent.kafka.schemaregistry.client.CachedSchemaRegistryClient.register(CachedSchemaRegistryClient.java:198)
at io.confluent.kafka.serializers.AbstractKafkaAvroSerializer.serializeImpl(AbstractKafkaAvroSerializer.java:70)
at io.confluent.kafka.serializers.KafkaAvroSerializer.serialize(KafkaAvroSerializer.java:53)
at org.apache.kafka.common.serialization.Serializer.serialize(Serializer.java:62)
at org.apache.kafka.clients.producer.KafkaProducer.doSend(KafkaProducer.java:903)
at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:865)
at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:752)
at belliPack.Kafka.Kafka_Producer.sendData(Kafka_Producer.java:32)
at belliPack.OPC.ExtractNodeValues.run(ExtractNodeValues.java:82)
at java.base/java.lang.Thread.run(Thread.java:834)```



问题来源：Stack Overflow