java - 不在 union ["null","int"] Avro 格式 org.apache.avro.UnresolvedUnionException

Question

我有一个 java 程序，它以 avro 格式从 Oracle db 写入数据。我在写作时在日期列上遇到了这个异常

org.apache.avro.file.DataFileWriter$AppendWriteException: org.apache.avro.UnresolvedUnionException: Not in union ["null","int"]: 2020-04-01

我正在使用 avro 1.9.2 版本。下面是架构：

{
  "type": "record",
  "name": "some",
  "doc": "SOME",
  "namespace": "some.avro",
  "fields": [
    {
      "name": "SOME_DATE",
      "type": [
        "null",
        "int"
      ],
      "logicalType": "date",
      "default": null
    }
..

  ]
}

当我将以下模式与字符串一起使用时，它工作正常。

{"name":"SOME_DATE","type": ["null","string"]}

Answer 1

您的架构应如下所示：

{
  "type": "record",
  "name": "some",
  "doc": "SOME",
  "namespace": "some.avro",
  "fields": [
    {
      "name": "SOME_DATE",
      "type": [
         "null",
         { "type": "int", "logicalType": "date" }
      ],
      "default": null
    }
  ..

  ]
}

但是，您可能会在转换具有默认值的联合类型和该联合内的逻辑类型时遇到一个令人讨厌的问题。))