如何将复杂对象映射到 DataWeave 固定宽度格式

Question

我有一个JSON对象

{
   "collection": [
      { 
         "field1": "1111",
         "field2": "1122"
      },
      { 
         "field1": "2211",
         "field2": "2222"
      }
   ],
   "otherObject": {
      "otherField": "3333"
   }
}

我想要这样的输出：

s01>1111~~~~~~1122~~~~~~

s01>2211~~~~~~2222~~~~~~

s02>3333~~~~~~

所以我使用了这个转换：

%dw 1.0
%output text/plain structureIdent = "response" , schemaPath = "response.ffd"

---
{
    collection: payload.collection map ({
        field1: $.field1,
        field2: $.field2
    }),
    otherObject: {
        otherField: payload.otherObject.otherField
    }
}

我的response.ffd是这样的

  form: FIXEDWIDTH
  structures:
  - id: 'response'
    name: response
    tagStart: 0
    data:
    - { idRef: 'collection', count: '>1'}
    - { idRef: 'otherObject', count: 1 }
  segments:
  - id: 'collection'
    name: collection
    tag: 's01>'
    values:
    - { name: 'field1', type: String, length: 10 }
    - { name: 'field2', type: String, length: 10 }
  - id: 'otherObject'
    name: otherObject
    tag: 's02>'
    values:
    - { name: 'otherField', type: String, length: 10 }

但我得到了这个结果

s02>3333~~~~~~

好像 dataweave 不知道我的数组，我应该怎么做才能让它工作？

Answer 1

使用以下示例修改 DataWeave 代码：

%dw 1.0
%output text/plain structureIdent = "response" , schemaPath = "response.ffd"
---
{
    collection: flatten [payload.collection map ({
        field1: $.field1,
        field2: $.field2
    })],
    otherObject: {
        otherField: payload.otherObject.otherField
    }
}

通过添加括号确保集合是数组：[ ... map ...]
使用 flatten 删除附加括号，因为 map 本身已经 return 一个数组

虽然它 return 是相同的结果，但 DataWeave 以某种方式对待它的方式不同，就好像数据结构是手动编写的一样：例如：

collection: [{
    field1: payload.collection.field1[0],
    field2: payload.collection.field2[0]
},{
    field1: payload.collection.field1[1],
    field2: payload.collection.field2[1]
}]

如何将复杂对象映射到 DataWeave 固定宽度格式

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