Mule 4：如何编写DataWeave表达式实现指定输出格式转换

输入示例 #

[
  {
    "payload": "[{\"qty\": 6.00, \"itemKey\": \"55555\"}]",
    "deliveryNote": "",
    "deliveryDate": "2022-10-22T00:00:00.000Z",
    "shoppingCartId": "2",
    "poNumber": "iisdown",
    "customerKey": "44444",
    "id": "9018A0000007OGrQAM"
  }
]

目标输出 #

{
  "id": "9018A0000007OGrQAM",
  "customerKey": "44444",
  "deliveryDate": "2022-10-22T00:00:00.000Z",
  "poNumber": "testingpo",
  "shoppingCartId": "2",
  "deliveryNote": "testing",
  "lines": [
    {
      "itemKey": "55555",
      "qty": 5
    }
  ]
}

DataWeave 表达式 #

%dw 2.0
output application/json
---
payload[0] mapObject (value, key) -> {
    (key): value 
} 
- "payload" 
++ {
    lines: read(payload[0].payload, "application/json") map (line) -> {
        itemKey: line.itemKey,
        qty: 5 as Number
    },
    poNumber: "testingpo",
    deliveryNote: "testing"
}

代码说明 #

1. 提取目标对象：输入是包含单个对象的数组，用payload[0]取出数组内的目标对象
2. 保留原有字段：通过mapObject遍历原对象的所有键值对，保留id、customerKey、deliveryDate、shoppingCartId这些不需要修改的字段
3. 移除冗余字段：用- "payload"删除原对象中的payload字段
4. 解析并转换lines数组：使用read()函数将原payload字段的JSON字符串解析为数组，再通过map遍历数组，修改qty为指定值5，保留itemKey
5. 替换指定字段值：直接给poNumber和deliveryNote赋值为需求中的新值，通过++合并到结果对象中

内容的提问来源于stack exchange，提问作者ilya.fastiv