java - Spring Data Mongodb 排序内部数组

Question

我一直在尝试根据日期对存储在文档列表中的项目进行排序。这是我的文档的结构:

{
  "_id": ObjectId("55c1940ce4b0a2a0482f22e8"),
  "eventId": "45b73f69-4804-4b50-84d0-6c551aa5bb5c",
  "isMacro": true,
  "isDeleted": false,
  "calendarEvent": [
    {
      "eventId": "b89a1519-ddff-4f71-9366-117e23c16d5c",
      "startDateTime": ISODate("2017-04-16T10:00:00.000Z")
    },
    {
      "eventId": "ecec8b3a-cf48-4f14-a7ac-14cd1a19f9da",
      "startDateTime": ISODate("2014-03-25T10:00:00.000Z")
    },
    {
      "eventId": "a002cc47-2939-4e75-9793-74720ebb7a21",
      "startDateTime": ISODate("2015-09-10T10:00:00.000Z")
    }
  ]
}

我想按 ASC 顺序对 calendarEvent 列表中的项目进行排序。我正在使用 Spring Data MongoDB。 这是我的代码:

AggregationOperation unwind = Aggregation.unwind("calendarEvent");
AggregationOperation match = Aggregation.match(criteria);
AggregationOperation project = getEventProjectionFields(); //private function which returns project object.
AggregationOperation sort = Aggregation.sort(Direction.ASC,
        "calendarEvent.startDateTime");

Aggregation aggregation = Aggregation.newAggregation(unwind, match,
        project, skip(0), limit(5), sort);

AggregationResults<Event> groupResults = mongoTemplate.aggregate(
        aggregation, mongoTemplate.getCollectionName(KAEvent.class),
        Event.class);

return groupResults.getMappedResults();

打印 aggregation.toString() 的值返回以下 JSON:

{
  "aggregate": "__collection__",
  "pipeline": [
    {
      "$unwind": "$calendarEvent"
    },
    {
      "$match": {
        "isMacro": true,
        "isDeleted": false,
        "$and": [
          {
            "eventId": {
              "$in": [
                "3d478f1a-9296-46b5-87d9-d0b442be0309",
                "4cbbe84b-6a35-4797-8c06-9b9b679ca48c"
              ]
            }
          },
          {
            "calendarEvent.eventId": {
              "$in": [
                "cb3fb7e7-5444-4ca5-8a6b-09e74bd346e4",
                "fec94eb6-160d-4608-8dae-5b43b88c550f",
                "e33d11a1-6d36-49ce-9e84-9b83ee9445dd"
              ]
            }
          }
        ],
        "calendarEvent.startDateTime": {
          "$gte": {
            "$date": "2015-10-13T07:42:48.841Z"
          }
        }
      }
    },
    {
      "$project": {
        "eventId": "$calendarEvent.eventId",
        "name": "$calendarEvent.name",
        "eventDescription": "$calendarEvent.eventDescription",
        "eventSummary": "$calendarEvent.eventSummary",
        "eventLocation": "$calendarEvent.eventLocation",
        "startDateTime": "$calendarEvent.startDateTime",
        "endDateTime": "$calendarEvent.endDateTime",
        "lastUpdateDate": "$calendarEvent.lastUpdateDate",
        "eventUrl": "$calendarEvent.eventUrl",
        "customImageUrl": "$calendarEvent.customImageUrl",
        "tagsList": "$calendarEvent.tagsList",
        "imagesList": "$calendarEvent.imagesList",
        "isFeatured": "$calendarEvent.isFeatured",
        "isDeleted": "$calendarEvent.isDeleted",
        "providerId": 1,
        "sourceId": 1,
        "isMacro": 1,
        "isCalendarEvent": 1,
        "_class": "$calendarEvent._class",
        "parenteventId": "$eventId"
      }
    },
    {
      "$skip": 0
    },
    {
      "$limit": 5
    },
    {
      "$sort": {
        "calendarEvent.startDateTime": 1
      }
    }
  ]
}

所有这些之后，返回的结果没有排序。我在这里遗漏了什么或做错了什么吗？

Answer 1

在投影新字段 startDateTime 后，您正在进行排序，该字段派生自嵌入字段 "calendarEvent.startDateTime"。

将排序管道更改为

AggregationOperation sort = Aggregation.sort(Direction.ASC,
        "startDateTime");