JOLT 转换：从多个 JSON 数组中提取字段并将其合并到单个数组输出

Question

我的JSON对象：

{
  "questionResponses": [
    {
      "responses": [
        {
          "responseId": "1",
          "response": "response 1"
        },
        {
          "responseId": "2",
          "response": "response 2"
        },
        {
          "responseId": "3",
          "response": "response 3"
        }
      ]
    }
  ],
  "answers": [
    {
      "questionId": "1",
      "answerId": "answer 1"
    },
    {
      "questionId": "1",
      "answerId": "answer 2"
    }
  ],
  "totalAttachments": 0
}

我需要以下格式的输出：

json prettyprint-override">[
  {
    "response": "response 1",
    "answerId": "answer 1"
  },
  {
    "response": "response 1",
    "answerId": "answer 2"
  },
  {
    "response": "response 2",
    "answerId": "answer 1"
  },
  {
    "response": "response 2",
    "answerId": "answer 2"
  },
  {
    "response": "response 3",
    "answerId": "answer 1"
  },
  {
    "response": "response 3",
    "answerId": "answer 2"
  }
]

我只有一个从两个数组中获取字段的解决方案，但是不确定如何在没有任何公共键的情况下连接它们，并以所需的方式表示它们

当前JOLT规格：

[
  {
    "operation": "shift",
    "spec": {
      "questionResponses": {
        "*": {
          "responses": {
            "*": {
              "response": "responses.[&1].response"
            }
          }
        }
      },
      "answers": {
        "*": {
          "answerId": "answers.[&1].answerId"
        }
      }
    }
  }
]

当前不希望的输出：

{
  "responses": [
    {
      "response": "response 1"
    },
    {
      "response": "response 2"
    },
    {
      "response": "response 3"
    }
  ],
  "answers": [
    {
      "answerId": "answer 1"
    },
    {
      "answerId": "answer 2"
    }
  ]
}

现在我必须将这些响应与每个answerId结合起来，以获得所需的输出。

此外，我使用Apache Nifi作为解决方案，如果JOLT transform不像预期的那样工作，我们可以使用其他方法/处理器吗？

Answer 1

您可以使用递归移位转换，首先在answers数组下获取键值对，然后浏览responses数组的子属性，例如

[
  {
    "operation": "shift",
    "spec": {
      "questionR*": {
        "*": {
          "responses": {
            "*": {
              "@(4,answers)": "@(1,response)"
            }
          }
        }
      }
    }
  },
  { 
   // Determine two independent arrays both with size of 6
    "operation": "shift",
    "spec": {
      "*": {
        "*": {
          "$1": "response",
          "a*": "&"
        }
      }
    }
  },
  {
   // expand those arrays as objects which contain desired key-value pairs
    "operation": "shift",
    "spec": {
      "*": {
        "*": "&.&1"
      }
    }
  },
  {
   // get rid of object labels
    "operation": "shift",
    "spec": {
      "*": ""
    }
  }
]