查询mongodb中匹配条件的文档及其所有子文档（使用spring）

Question

我有一个MongoDB存储来自不同传感器的数据。它具有以下结构：

 {
     "_id" : 1,
     "sensorName" : "Heart Rate",
     "samplePeriod" : 1000,
     "data" : [
             {
                 "timestamp" : NumberLong("1483537204046"),
                 "dataPoints" : [ 68 70 ]
             },
             {
                 "timestamp" : NumberLong("1483537206046"),
                 "dataPoints" : [ 68 70 ]
             }
     ]
}
{
    "_id" : 2,
    "sensorName" : "Ambient Light",
    "samplePeriod" : 500,
    "data" : [
            {
                "timestamp" : NumberLong("1483537204058"),
                "dataPoints" : [ 56, 54, 54, 54 ]
            },
            {
                "timestamp" : NumberLong("1483537206058"),
                "dataPoints" : [ 56, 54, 54, 54 ]
            }
    ]
}

例如，现在我需要“heart rate”-文档的所有字段和“data”-子文档的所有字段都符合条件“时间戳在1483537204000和1483537214000之间”。

aggregate([{
    $match: {
        "_id": 1
    }
}, {
    "$project": {
        "_id": 1,
        "sensorName": 1,
        "samplePeriod": 1,
        "data": {
            "$filter": {
                "input": "$data",
                "as": "result",
                "cond": {
                    $and: [{
                        $gte: ["$$result.timestamp", 1483537204000]
                    }, {
                        $lte: ["$$result.timestamp", 1483537214000]
                    }]
                }
            }
        }
    }
}])

Answer 1

您需要使用spring mongo数据依赖项中提供的MongoTemplate。当前版本中没有对$filter的开箱即用支持。利用ActivisionExpression。在项目中包括以下预测。使用1.8.5 spring mongo数据版本。

Aggregation aggregation = newAggregation(
        match(Criteria.where("_id").is(1)),
        project( "_id", "sensorName", "samplePeriod").and(new AggregationExpression() {
            @Override
            public DBObject toDbObject(AggregationOperationContext aggregationOperationContext) {
                DBObject filter = new BasicDBObject("input", "$data").append("as", "result").append("cond",
                        new BasicDBObject("$and", Arrays.<Object> asList(new BasicDBObject("$gte", Arrays.<Object> asList("$$result.timestamp", 1483537204000L)),
                                new BasicDBObject("$lte", Arrays.<Object> asList("$$result.timestamp", 1483537214000L)))));
                return new BasicDBObject("$filter", filter);
            }
        }).as("data")
);

List<BasicDBObject> dbObjects = monoTemplate.aggregate(aggregation, "collectionname", BasicDBObject.class).getMappedResults();