如何在Java代码中使用MongoDB聚合过滤嵌套列表？

需求目标 #

• 过滤Item中的prices数组，满足以下任一条件：
  1. validFor为空对象，或validFor.endDateTime晚于当前日期
• 过滤prices下的alterations数组，仅保留finalPrice ≥ 110的项

示例JSON数据 #

{"id": 1,"prices": [{"priceName": "price1","validFor": {},"alterations": [{"alterationName": "alteration1","finalPrice": 110}]},{"priceName": "price2","validFor": {"endDateTime": "2024-10-31T12:00:00Z"},"alterations": [{"alterationName": "alteration2","finalPrice": 105},{"alterationName": "alteration3","finalPrice": 115}]}]}

对应的MongoDB原生聚合查询 #

[
  {
    "$project": {
      "id": 1,
      "prices": {
        "$filter": {
          "input": "$prices",
          "as": "price",
          "cond": {
            "$or": [
              {"$eq": ["$$price.validFor", {}]},
              {"$gt": [{"$dateFromString": {"dateString": "$$price.validFor.endDateTime","format": "%Y-%m-%dT%H:%M:%S%z"}}, new Date()]}
            ]
          }
        }
      }
    }
  },
  {
    "$project": {
      "id": 1,
      "prices": {
        "$map": {
          "input": "$prices",
          "as": "price",
          "in": {
            "$mergeObjects": [
              "$$price",
              {"alterations": {"$filter": {"input": "$$price.alterations","as": "alteration","cond": {"$gte": ["$$alteration.finalPrice",110]}}}}
            ]
          }
        }
      }
    }
  }
]

当前Java代码卡点 #

我已经能把聚合结果转成Item列表，但在实现聚合逻辑时，卡在字符串类型的endDateTime与当前日期的比较环节。目前写的代码片段如下：

aggregationOperations.add(Aggregation.project()
    .and(when(new Criteria().orOperator(
        new Criteria("price.validFor").is(new Document()),
        new Criteria("price.validFor.endDateTime").gt(new Date().toString())
    )).then(true).otherwise(false)).as("prices"));

内容的提问来源于stack exchange，提问作者Tom