无法使用avro数组类型反序列化json

Question

尝试使用apache avro反序列化json时出现以下异常：

Exception in thread "main" org.apache.avro.AvroTypeException: Unknown union branch sampleArrayRecordString
    at org.apache.avro.io.JsonDecoder.readIndex(JsonDecoder.java:445)

以下是代码：

final Schema schema = Schema.parse(new File(
        "<schema_file_path>"));
byte[] payload = Files.readAllBytes(Paths.get(
        "<json_file_path>"));

GenericRecord record = new GenericDatumReader<GenericRecord>(schema).read(null,
        DecoderFactory.get().jsonDecoder(schema, new String(payload)));

System.out.println(record);

以下是架构：

{
   "type":"record",
   "name":"SampleEvent",
   "namespace":"a.b",
   "doc":"Avro definition for sample data.",
   "fields":[
      {
         "name":"eventBody",
         "type":[
            {
               "type":"record",
               "name":"SampleBody",
               "doc":"Avro definition",
               "fields":[
                  {
                     "name":"sampleArray",
                     "type":{
                       "type":"array",
                       "items":[
                        {
                          "name":"sampleArrayRecord",
                          "type":"record",
                          "fields":[
                            {
                              "name":"sampleArrayRecordString",
                              "type":"string",
                              "doc":"Sample array record string",
                              "omdFieldSecurity":"internal",
                              "omdLogicalDataType":"string"
                            }
                          ],
                          "doc":"Sample array record",
                          "omdFileSecurity":"internal",
                          "omdRepositoryTag":"1.4.0"
                        }
                       ]
                     },
                     "doc":"Sample array",
                     "omdFieldSecurity":"internal",
                     "omdLogicalDataType":"record"
                  }
               ],
               "omdSecurityClassification":"Internal",
               "omdRepositoryTag":"1.0.0"
            }
         ]
      }
   ]
}

最后，下面是json：

{
    "eventBody": {
        "a.b.SampleBody": {
            "sampleArray": [{
                "sampleArrayRecordString": "KLMNO"
            }]
        }
    }
}

我是否需要指定任何元数据才能使其生效？