如何在NiFi中使用JOLTTransforms实现指定JSON格式转换？

输入JSON #

[
  {
    "ExchangeCurrency": "INR",
    "FExchangeCurrency": "AUD",
    "ExchangeRate": 123,
    "ExchangeDate2": "2023-05-01"
  },
  {
    "ExchangeCurrency": "INR",
    "FExchangeCurrency": "CHF",
    "ExchangeRate": 234,
    "ExchangeDate2": "2023-05-01"
  },
  {
    "ExchangeCurrency": "INR",
    "FExchangeCurrency": "EUR",
    "ExchangeRate": 456,
    "ExchangeDate2": "2023-05-01"
  }
]

预期输出JSON #

{
  "ExchangeCurrency" : "INR",
  "ExchangeDate2" : "2023-05-01",
  "AUD_ExchangeRate" : 123,
  "CHF_ExchangeRate" : 234,
  "EUR_ExchangeRate" : 456
}

JOLT转换规则 #

[
  {
    "operation": "shift",
    "spec": {
      "*": {
        "ExchangeCurrency": "ExchangeCurrency",
        "ExchangeDate2": "ExchangeDate2",
        "ExchangeRate": "@(1,FExchangeCurrency)_ExchangeRate"
      }
    }
  },
  {
    "operation": "sort",
    "spec": {
      "ExchangeCurrency": 1,
      "ExchangeDate2": 2,
      "*_ExchangeRate": 3
    }
  }
]

规则说明 #

• Shift操作：遍历输入数组的每个元素，提取统一的ExchangeCurrency和ExchangeDate2字段；将每个元素的ExchangeRate值映射到[FExchangeCurrency值]_ExchangeRate格式的键名下。
• Sort操作：指定字段排序优先级，确保ExchangeCurrency、ExchangeDate2排在最前，所有汇率相关字段紧随其后，满足输出顺序要求。

内容的提问来源于stack exchange，提问作者pandu