当我只想要父对象时，JSONPath 查询从嵌套对象返回同名键

Question

我目前正在使用 Pentaho Kettle 进行一些 ETL 工作，我需要集成一个 JSON 提要，这意味着我需要使用 JSONPath 来抓取数据。在大多数情况下，它运行良好，除了一些 JSON 数据是嵌套对象，在父项和子项中具有相同的字段名称。

示例 JSON:

[
  {
    "Key": "5e59d536-2e3c-487c-bff1-efd0a706532f",
    "Product": {
      "Name": "Some Product",
      "LastUpdated": "2013-08-23T12:10:25.454",
    },
    "Reviewer": {
      "Email": "blah@foo.com",
      "LastUpdated": "2013-08-23T12:10:25.454",
    },
    "LastUpdated": "2013-08-23T12:10:25.407",
  },
  {
    "Key": "f3ae6a4b-1a20-4a9a-9a8e-2de5949c4493",
    "Product": {
      "Name": "Some Product",
      "LastUpdated": "2013-08-23T12:10:51.896",
    },
    "Reviewer": {
      "Email": "blah@foo.com",
      "LastUpdated": "2013-08-23T12:10:51.896",
    },
    "LastUpdated": "2013-08-23T12:10:51.896",
  },
  {
    "Key": "de01c358-6c74-473c-8cd4-a44cf50132df",
    "Product": {
      "Name": "Some Product",
      "LastUpdated": "2013-08-26T10:30:13.617",
    },
    "Reviewer": {
      "Email": "blah@foo.com",
      "LastUpdated": "2013-08-26T10:30:13.617",
    },
    "LastUpdated": "2013-08-26T10:30:13.601",
    },
  },
  {
    "Key": "af04e48a-3ce8-4227-a00a-14483ca75058",
    "Product": {
      "Name": "Some Product",
      "LastUpdated": "2013-08-26T10:31:20.573",
    },
    "Reviewer": {
      "Email": "blah@foo.com",
      "LastUpdated": "2013-08-26T10:31:20.573",
    },
    "LastUpdated": "2013-08-26T10:31:20.573",
  },
  {
    "Key": "d1a787bb-37d2-4ea9-84fd-5a3d454b9127",
    "Product": {
      "Name": "Some Product",
      "LastUpdated": "2013-08-27T11:59:56.777",
    },
    "Reviewer": {
      "Email": "blah@foo.com",
      "LastUpdated": "2013-08-27T11:59:56.777",
    },
    "LastUpdated": "2013-08-27T11:59:56.73",
  },
  {
    "Key": "d8646319-af27-464f-bd50-d61e035800c6",
    "Product": {
      "Name": "Some Product",
      "LastUpdated": "2013-08-27T19:43:06.928",
    },
    "Reviewer": {
      "Email": "blah@foo.com",
      "LastUpdated": "2013-08-27T19:43:06.928",
    },
    "LastUpdated": "2013-08-27T19:43:06.866",
  },
]

如您所见，父对象及其子对象“Product”和“Reviewer”都有“LastUpdated”字段。我试图仅获取父对象的“LastUpdated”，但使用:

$..LastUpdated

按顺序返回父 LastUpdated、Product LastUpdated，然后是 Reviewer LastUpdated。

结果:

[
   "2013-08-23T12:10:25.407",
   "2013-08-23T12:10:25.454",
   "2013-08-23T12:10:25.454",
   "2013-08-23T12:10:51.896",
   "2013-08-23T12:10:51.896",
   "2013-08-23T12:10:51.896",
   "2013-08-26T10:30:13.601",
   "2013-08-26T10:30:13.617",
   "2013-08-26T10:30:13.617",
   "2013-08-26T10:31:20.573",
   "2013-08-26T10:31:20.573",
   "2013-08-26T10:31:20.573",
   "2013-08-27T11:59:56.73",
   "2013-08-27T11:59:56.777",
   "2013-08-27T11:59:56.777",
   "2013-08-27T19:43:06.866",
   "2013-08-27T19:43:06.928",
   "2013-08-27T19:43:06.928"
]

预期结果:

[
   "2013-08-23T12:10:25.407",
   "2013-08-23T12:10:51.896",
   "2013-08-26T10:30:13.601",
   "2013-08-26T10:31:20.573",
   "2013-08-27T11:59:56.73",
   "2013-08-27T19:43:06.866",
]

有没有我可以用来仅获取父对象的 LastUpdated 字段的查询？

Answer 1

终于明白了:

$[*].LastUpdated -> only the parents
$[*].Product.LastUpdated -> only the product
$[*].Reviewer.LastUpdated -> only the reviewer