Mule4 DataWeave JSON转换需求：面糊与配料组合生成甜甜圈数据

输入JSON #

{
  "type": "donut",
  "weight-unit": "lb",
  "price-unit": "$/lb",
  "price": 10.75,
  "batters": {
    "batter": [
      {"id": "10011", "type": "Original", "weight": 500},
      {"id": "10021", "type": "Chocolate", "weight": 200, "price": 11.75},
      {"id": "10031", "type": "Blueberry", "weight": 250, "price": 11.75},
      {"id": "10041", "type": "Devil's Food", "weight": 150}
    ]
  },
  "topping": [
    {"id": "50011", "type": "None", "price": 0},
    {"id": "50021", "type": "Glazed", "price": 45.23},
    {"id": "50051", "type": "Sugar", "price": 34.1},
    {"id": "50071", "type": "Powdered Sugar", "price": 21.11},
    {"id": "50061", "type": "Chocolate with Sprinkles", "price": 34.43},
    {"id": "50031", "type": "Chocolate", "price": 87.40},
    {"id": "50041", "type": "Maple", "price": 64.11}
  ]
}

期望输出JSON（注：原示例存在重复key问题，已修正为合法JSON结构） #

{
  "type": "donut",
  "ChocolateFlavoredGlazedDonut": {
    "weight": 200,
    "weightUnit": "kg",
    "price": 56.98,
    "priceUnit": "$/kg"
  },
  "ChocolateFlavoredSprinklesDonut": {
    "weight": 200,
    "weightUnit": "kg",
    "price": 46.18,
    "priceUnit": "$/kg"
  },
  "BlueberryFlavoredSugarDonut": {
    "weight": 250,
    "weightUnit": "kg",
    "price": 45.85,
    "priceUnit": "$/kg"
  },
  "OriginalGlazedDonut": {
    "weight": 500,
    "weightUnit": "kg",
    "price": 45.23,
    "priceUnit": "$/kg"
  },
  "OriginalMapleDonut": {
    "weight": 500,
    "weightUnit": "kg",
    "price": 64.11,
    "priceUnit": "$/kg"
  },
  "OriginalSugarDonut": {
    "weight": 500,
    "weightUnit": "kg",
    "price": 34.1,
    "priceUnit": "$/kg"
  }
}

转换规则 #

• 每个面糊（batter）与每个配料（topping）组合生成一个键值对，键名为「面糊名称+Flavored+配料名称（去除空格）+Donut」格式的驼峰命名
• 每个键对应的值结构：
  • weight：取对应面糊的weight字段值
  • weightUnit：硬编码为"kg"
  • price：面糊的price字段值（无该字段则取0）与配料的price字段值之和
  • priceUnit：硬编码为"$/kg"

DataWeave 2.0 转换代码 #

%dw 2.0
output application/json
---
{
    type: payload.type,
    (payload.batters.batter flatMap (batter) -> 
        payload.topping map (topping) -> {
            ("$(batter.type)Flavored$(topping.type replace /\s+/ with '')Donut"): {
                weight: batter.weight,
                weightUnit: "kg",
                price: (batter.price default 0) + topping.price,
                priceUnit: "$/kg"
            }
        }
    ) reduce ($$ ++ $)
}

代码说明 #

1. 保留原输入的type字段
2. 使用flatMap遍历所有面糊，再用map遍历每个配料，生成所有组合的键值对
3. 通过reduce将多个对象合并为一个对象，实现所有组合的聚合
4. 对配料名称做空格去除处理，确保键名格式符合示例要求
5. 用default 0处理面糊无price字段的情况，避免空值错误

内容的提问来源于stack exchange，提问作者aparajita tiwary