将嵌套的 json 数组映射到 CSV

Question

我正在尝试将数组有效负载映射到 Dataweave 中的 CSV，但无法获得结果。

csv 不需要标题，数组中的内容将逐列打印。我在通过嵌套数组进行映射时遇到问题。

输入负载

[
  {
  "Invoice": {
    "Invoice Number*": "Test",
    "Supplier Number": "1201",
    "Submit For Approval?": "Yes",
    "Invoice Date*": "20190828",
    "Line Level Taxation*": "Yes",
    "Payment Date": "00/00/0000",
    "Original invoice number": "",
    "Original invoice date": ""
  },
  "Invoice Line": [
    {
      "Invoice Number*": "Test1",
      "Line Number": "1",
      "Description*": "Test1",
      "Price*": "500",
      "Quantity": null,
      "Unit of Measure*": null,
      "PO Number": "001",
      "PO Line Number": "1"
    },
    {
      "Invoice Number*": "Test2",
      "Line Number": "2",
      "Description*": "Test2",
      "Price*": "500",
      "Quantity": null,
      "Unit of Measure*": null,
      "PO Number": "001",
      "PO Line Number": "2"
    }
  ],
  "Invoice Tax Line": [
     {
       "Tax Amount": "500",
       "Invoice Line Number": "1",
       "Line Number": "1"
     },
     {
       "Tax Amount": "50",
       "Invoice Line Number": "2",
       "Line Number": "2"
     }
  ]
  }
]

预期输出

column_0, column_1, column_2 ... //no header
"Invoice Number*","Supplier Number","Submit For Approval?"... //Invoice
"Invoice Number*","Line Number*"...                        //InvoiceLine[0]
"Tax Amount","Invoice Line Number","Line Number"...        //Tax Line[0]
"Invoice Number*","Line Number*"...                        //InvoiceLine[1]
"Tax Amount","Invoice Line Number","Line Number"...        //Tax Line[1]

如何编写 dataweave 映射来归档上述结果？

Answer 1

这是我为您的用例找到的解决方案。基本上有两个函数可以根据类型在正确的方法上分派。然后您还想使用zip 函数将一个“发票行”与一个“发票税行”混合，以便正确混合。

%dw 2.0
output application/csv headers=false 
import * from dw::core::Objects

fun collectKeyNames(obj: {}): Array<{}> = 
            [
                obj
            ]

fun collectKeyNames(arr: Array): Array<{}> = 
    arr flatMap ((obj, index) ->  collectKeyNames(obj))

---
payload flatMap ((item, index) -> 
    collectKeyNames(item.Invoice) ++ 
        (collectKeyNames(item."Invoice Line" zip item."Invoice Tax Line"))
)