Spring数据mongodb - 聚合框架集成

作者: ⑩Ⅵ嵗Ｄ夨憶
发布时间: 2025-02-11 07:58:03 (16天前)
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遇见你 | 2019-08-31 10-32

<div class =“post-text”itemprop =“text”> <P> 以下是获取特定字段总和的方法。 </p> <pre> <code> private Map<String, Long> getTotalMap(){ /* db.pDSSummaryModel.aggregate([{ $group: { _id: null, total: { $sum: '$totalUniqueCustomerCount' } } }]) */ Aggregation aggregations = newAggregation( group("null").sum("totalUniqueUserCount").as("userTotal") .sum("totalUniqueCustomerCount").as("customerTotal"), project("customerTotal", "userTotal") ); AggregationResults<DBObject> results = mongoTemplate.aggregate(aggregations, "pDSSummaryModel", DBObject.class); List<DBObject> fieldList = results.getMappedResults(); Map<String, Long> map = new HashMap<>(); if(fieldList != null && !fieldList.isEmpty()) { for(DBObject db: fieldList){ map.put("userTotal", parseLong(db.get("userTotal").toString())); map.put("customerTotal", parseLong(db.get("customerTotal").toString())); } } return map; } </code> </pre> </DIV>

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SHOU宅大可爱 | 2019-08-31 10-32

<div class =“post-text”itemprop =“text”> <P> 春季数据 <code> MongoOperations.group() </code> 方法映射到 <code> db.collection.group() </code> MongoDB命令而不是 <code> $group </code> 聚合功能。目前，Spring Data MongoDB不支持聚合框架。正如您所提到的，Map reduce虽然受到支持 </p> </DIV>

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求赞有赞必回 | 2019-08-31 10-32

<div class =“post-text”itemprop =“text”> <pre> <code> Aggregation aggregation = newAggregation( match(Criteria.where("salesyear").is(year)), group("brand","salesyear").sum("numberOfCars").as("total"), sort(Sort.Direction.ASC, previousOperation(), "brand") ); </code> </pre> </DIV>

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疯子哥哥 | 2019-08-31 10-32

<div class =“post-text”itemprop =“text”> <P> Spring Data 1.3.0.RC1可用，它确实支持聚合框架。 </p> <P> 例如： shell聚合命令： </p> <pre> <code> db.eft_transactions.aggregate( {$match: { service:"EFT", source:"MARKUP", } }, {$group: { _id:"$card_acceptor_id", tran_count:{$sum:1}, amount_sum:{$sum:"$amount"} } } ) </code> </pre> <P> 从java运行如下： </p> <pre> <code> AggregationOperation match = Aggregation.match(Criteria.where("service").is("EFT").and("source").is("MARKUP")); AggregationOperation group = Aggregation.group("card_acceptor").and("amount_sum").sum("amount").and("tran_count").count(); Aggregation aggregation = newAggregation(match, group); AggregationResults<StoreSummary> result = this.mongoTemplate.aggregate(aggregation, "eft_transactions", StoreSummary.class); </code> </pre> <P> 文档是 <a href="http://static.springsource.org/spring-data/data-mongodb/docs/1.3.0.RC1/reference/htmlsingle/#mongo.aggregation"> 这里 </A> </p> <P> 注意：我们最近不得不切换到使用版本1.3.0的BUILD-SNAPSHOT版本。此更改需要更改上述两行已更改为： </p> <pre> <code> AggregationOperation group = Aggregation.group("card_acceptor").sum("amount").as("amount_sum").count().as("tran_count"); Aggregation aggregation = Aggregation.newAggregation(match, group); </code> </pre> </DIV>

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