java - 类型不匹配 : cannot convert from Map> 到 ConsumerRecords

Question

当我尝试运行我的 SupplierConsumer 时遇到这些错误 eclipse 中的类。这是我的代码:

public class SupplierConsumer{

    public static void main(String[] args) throws Exception{

            String topicName = "SupplierTopic";
            String groupName = "SupplierTopicGroup";

            Properties props = new Properties();
            props.put("bootstrap.servers", "localhost:9092,localhost:9093");
            props.put("group.id", groupName);
            props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
            props.put("value.deserializer", "SupplierDeserializer");


            KafkaConsumer<String, Supplier> consumer = new KafkaConsumer<>(props);
            consumer.subscribe(Arrays.asList(topicName));

            while (true){
                    ConsumerRecords<String, Supplier> records = consumer.poll(100);
                    for (ConsumerRecord<String, Supplier> record : records){
                            System.out.println("Supplier id= " + String.valueOf(record.value().getID()) + " Supplier  Name = " + record.value().getName() + " Supplier Start Date = " + record.value().getStartDate().toString());
                    }
            }
    }
}

1. 类型不匹配:无法从 List<String> 转换至String ,
2. 类型不匹配:无法从 Map<String,ConsumerRecords<String,Supplier>> 转换至ConsumerRecords<String,Supplier>

Answer 1

我认为您无意中在类路径中包含了 kafka-clients 库的一些预发布版本。我在 v0.8.2-beta 中找到了与您的编译错误相符的签名:

http://supergsego.com/apache/kafka/0.8.2-beta/java-doc/org/apache/kafka/clients/consumer/KafkaConsumer.html

如果您确保使用 kafka-clients jar 的发布质量版本(v0.9 或更高版本)，您的代码应该可以编译。