Question

全部。我正在尝试使用条件更改json中数组元素的字段值：如果“ field1”的值等于“ value1”，则将字段“ changethisfield”的值更改为“ new_value”。当前有效载荷：

    {
      "message": [
        {
          "field1": "value1",
          "field2": "value2",
          "changethisfield": ""
        },
        {
          "field1": "value3",
          "field2": "value4",
          "changethisfield": ""
        }
      ]
    }

Dataweave代码：

    %dw 2.0
    output application/json

    var itemValue = payload.message map (item) -> {
        (item mapObject (value, key, index) -> {
            ((key): value) if (key as String != 'changethisfield'),
            (changethisfield: "new_value") if (key as String == 'changethisfield')
        })
    }

    ---

    {
        "message": {
            item: itemValue
        }
    }

但是此代码更改了数组所有元素的值（当前输出）：

{
  "message": {
    "item": [
      {
        "field1": "value1",
        "field2": "value2",
        "changethisfield": "new_value"
      },
      {
        "field1": "value3",
        "field2": "value4",
        "changethisfield": "new_value"
      }
    ]
  }
}

所需的输出（只有“ field1”包含“ value1”的“ changethisfield”项目的值应更改为“ new_value”）：

{
  "message": {
    "item": [
      {
        "field1": "value1",
        "field2": "value2",
        "changethisfield": "new_value"
      },
      {
        "field1": "value3",
        "field2": "value4",
        "changethisfield": ""
      }
    ]
  }
}

请帮助您理解如何在数组元素中创建条件并解决此任务。谢谢！

Answer 1

这应该有效：

%dw 2.0
output application/dw

var data =     {
      "message": [
        {
          "field1": "value1",
          "field2": "value2",
          "changethisfield": ""
        },
        {
          "field1": "value3",
          "field2": "value4",
          "changethisfield": ""
        }
      ]
    }

---
message: data.message map {
    ($ - "changethisfield"),
    changethisfield: if ($.field1 == "value1") "new_value" else $.changethisfield
}

Answer 2

希望添加您也可以使用update函数，而不是删除将字段手动添加到对象的方法。这也可以将数组中的每个项目都更改为特定值，但是由于您有条件，因此必须在地图内执行。

比较的问题是，仅当键是特定字符串时，才将比较作为对象级别进行。您无需检查field1是否具有特定值。

%dw 2.0
output application/json
import * from dw::util::Values

var inputData =     {
      "message": [
        {
          "field1": "value1",
          "field2": "value2",
          "changethisfield": ""
        },
        {
          "field1": "value3",
          "field2": "value4",
          "changethisfield": ""
        }
      ]
    }

---
{
    message: inputData.message map ((item, index) -> (
        if (item.field1 == "value1") (
            item update "changethisfield" with "newValue"
        ) else (
            item
        )
    ))
}

仅当条件为真时才更改数组元素中json的字段

2 个答案: