Question

我有一个问题，在任何其他语言中我都需要十秒钟，但在这里我无法用Dataweave解决它。

我的JSON看起来像这样：

{
    "100": [{
        "courseID": "100",
        "course": "physics",
        "instructor": "John S",
        "section": "A",
        "date": "01-01-1900"
    }],
    "200": [{
        "courseID": "200",
        "course": "math",
        "instructor": "Jim R",
        "section": "A",
        "date": "01-03-1900"
    },
    {
        "courseID": "200",
        "course": "math",
        "instructor": "Jim R",
        "section": "B",
        "date": "01-07-1900"
    },
    {
        "courseID": "200",
        "course": "math",
        "instructor": "Jim R",
        "section": "C",
        "date": "01-08-1900"
    }

    ]}
}

我确定数组中的对象包含重复的信息，但截面和日期除外。所以我需要压缩它并将其转换成：

{
    "courses": [{
        "courseID": "100",
        "course": "physics",
        "instructor": "John S",
        "sections": [{
            "section": "A",
            "date": "01-01-1900"
        }]
    },
    {
        "courseID": "200",
        "course": "math",
        "instructor": "Jim R",
        "sections": [{
            "section": "A",
            "date": "01-03-1900"
        },
        {
            "section": "B",
            "date": "01-07-1900"
        },
        {
            "section": "C",
            "date": "01-08-1900"
        }]
]}

我无法做到这一点。我已经尝试了使用map（），mapObject（）和pluck（）迭代文档的各种方法。它们需要嵌套我想，我只想从它迭代的第一个过程中提取ID，课程和讲师，然后继续使用section数据构建对象。嵌套似乎会导致问题，因为存在混合的对象和数组，如果嵌套函数返回错误的类型，则map（）和mapObject（）会抱怨。这是我一直没有成功的尝试：

%dw 2.0
output application/json
---
"courses": payload.pluck(courseValue, courseKey, courseIndex) -> 
               courseValue map (classValue, classKey, classIndex) ->
                   { courseID: classValue.courseID,
                     instructor: classValue.instructor
                     etc...
 }

我希望一切都清楚。我很长时间没有弄乱它了。是否有可能我想做的事情太复杂而DW无法处理，我应该使用另一种方法吗？

Answer 1

此解决方案应适用于所有DataWeave版本

courses: (payload pluck $$) map using (c = payload[$]) {
  courseID : $,
  course: c[0].course,
  instructor: c[0].instructor,
  sections: c map {
    section: $.section,
    date: $.date
  }
}

此解决方案适用于Mule 3.x但不适用于4.x，本博客文章在“从对象到数组的自动强制”下解释了这些解决方案＆＃39;：https://blogs.mulesoft.com/dev/mule-dev/dataweave-mule-4-beta-syntax-changes-part-1/

courses: payload map {
  courseID: $[0].courseID,
  course: $[0].course,
  instructor: $[0].instructor,
  sections: $ map {
    section: $.section,
    date: $.date
  }
}

Answer 2

我看到您正在使用DataWeave 2.0。这是您可以使用的简单DataWeave转换器。

<强>变压器：

        <ee:transform doc:name="Transform Message" >
            <ee:message >
                <ee:set-payload ><![CDATA[%dw 2.0
output application/json
---
{
    courses: (payload pluck $$) map ((courseValue, courseKey) -> {
        courseID: payload[courseValue][0].courseID,
        course: payload[courseValue][0].course,
        instructor: payload[courseValue][0].instructor,
        sections: payload[courseValue] map ((sectionValue, sectionKey) -> {
            section: sectionValue.section,
            date: sectionValue.date
        }) 
    })  
}
]]></ee:set-payload>
            </ee:message>
        </ee:transform>

<强>输入：

{
  "100": [
    {
      "courseID": "100",
      "course": "physics",
      "instructor": "John S",
      "section": "A",
      "date": "01-01-1900"
    }
  ],
  "200": [
    {
      "courseID": "200",
      "course": "math",
      "instructor": "Jim R",
      "section": "A",
      "date": "01-03-1900"
    },
    {
      "courseID": "200",
      "course": "math",
      "instructor": "Jim R",
      "section": "B",
      "date": "01-07-1900"
    },
    {
      "courseID": "200",
      "course": "math",
      "instructor": "Jim R",
      "section": "C",
      "date": "01-08-1900"
    }
  ]
}

<强>输出：

{
  "courses": [
    {
      "courseID": "100",
      "course": "physics",
      "instructor": "John S",
      "sections": [
        {
          "section": "A",
          "date": "01-01-1900"
        }
      ]
    },
    {
      "courseID": "200",
      "course": "math",
      "instructor": "Jim R",
      "sections": [
        {
          "section": "A",
          "date": "01-03-1900"
        },
        {
          "section": "B",
          "date": "01-07-1900"
        },
        {
          "section": "C",
          "date": "01-08-1900"
        }
      ]
    }
  ]
}

有没有办法用Dataweave地图创建更灵活的循环？

2 个答案: