Question

我试图利用以下图表和JSON数据生成Avro GenericRecord。

Avro schema

{
  "type": "record",
  "name": "Person",
  "fields": [
    {
      "name": "name",
      "type": "string"
    },
    {
      "name": "age",
      "type": "int"
    },
    {
      "name": "city",
      "type": "string"
    },
    {
      "name": "gender",
      "type": {
        "type": "enum",
        "name": "Gender",
        "symbols": ["MALE", "FEMALE"]
      }
    }
  ]
}

JSON数据

{"name": "John", "age": 30, "city": "New York", "gender": "MALE"}

守则一用于生成通用记录。

public class Main {

    public static void main(String[] args) throws IOException {
        Schema schema = readSchema();
        JsonNode data = readData();
        GenericRecord genericRecord = convertJsonToAvro(data, schema);
        System.out.println(genericRecord);
    }

    public static GenericRecord convertJsonToAvro(JsonNode jsonNode, Schema avroSchema) throws IOException {
        DatumReader<GenericRecord> reader = new GenericDatumReader<>(avroSchema);
        Decoder decoder = DecoderFactory.get().jsonDecoder(avroSchema, jsonNode.toString());
        return reader.read(null, decoder);
    }

    private static Schema readSchema() throws IOException {
        InputStream inputStream = Main.class.getClassLoader().getResourceAsStream("schemas/person.avsc");
        return new Schema.Parser().parse(inputStream);

    }

    private static JsonNode readData() throws IOException {
        InputStream inputStream = Main.class.getClassLoader().getResourceAsStream("sample_data/person.json");
        ObjectMapper objectMapper = new ObjectMapper();
        return objectMapper.readValue(inputStream, JsonNode.class);
    }

}

从上述法典来看,我能够成功地产生一种通用记录。但是,当图谋领域改成像以下这样的选择领域时,就会犯错误。

D. 任择领域

{
    "name": "gender",
    "type": [
        "null",
        {
            "type": "enum",
            "name": "Gender",
            "symbols": ["MALE", "FEMALE"]
        }
    ],
    "default": null
}

错误

Exception in thread "main" org.apache.avro.AvroTypeException: Expected start-union. Got VALUE_STRING
at org.apache.avro.io.JsonDecoder.error(JsonDecoder.java:511)
at org.apache.avro.io.JsonDecoder.readIndex(JsonDecoder.java:430)
at org.apache.avro.io.ResolvingDecoder.readIndex(ResolvingDecoder.java:282)
at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:188)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:161)
at org.apache.avro.generic.GenericDatumReader.readField(GenericDatumReader.java:260)
at org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:248)
at org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:180)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:161)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:154)
at com.generic.Main.convertJsonToAvro(Main.java:27)
at com.generic.Main.main(Main.java:20)

FAILURE: Build failed with an exception.

我非常赞赏有人能够解释这里发生的情况以及纠正这一错误的方法。我知道allegro/json-avro-converter,但我不想这样做。守则的例子将非常有益。

请找到上述法典所用的属性。

implementation group:  org.apache.avro , name:  avro , version:  1.11.3 
implementation group:  com.fasterxml.jackson.core , name:  jackson-core , version:  2.16.0

Answer 1

UPDATED

a 不包括: 有效载荷:

{"name": "John", "age": 30, "city": "New York", "gender": {"Gender": "MALE"}}

随后是<代码>GenericRecord:

{"name": "John", "age": 30, "city": "New York", "gender": "MALE"}

这是一份无效的<条码>。有效载荷

{"name": "John", "age": 30, "city": "New York", "gender": null}

友情链接