在Java中将包括$ cond的聚合转换为DBObject

本文介绍了在Java中将包括$ cond的聚合转换为DBObject的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我已经在MongoDB中构建了一个聚合

I have build an aggregation in MongoDB

{ "$project": { "dt": "$dt", "mc": "$mc", "uplift": "$uplift", "baseAvg": "$baseAvg", "baseUp": { $add: [ "$uplift", "$baseAvg" ] }, "share": { "$cond": [{ "$eq": ["$baseAvg", 0] }, 0, { "$divide": ["$uplift", "$baseAvg"] }] } } }

由于没有支持条件的ProjectOperation，因此我尝试使用DBObject构建查询.但是我被卡住了.

I'm trying to build the query by using DBObject since there is no ProjectOperation that supports condition. But I get stuck.

当我写这篇文章时:

ArrayList condArray = new ArrayList(); condArray.add(new BasicDBObject("$eq", new DBObject[] { new BasicDBObject("$baseAvg", 0) })); condArray.add(0); condArray.add(new BasicDBObject("$divide", new DBObject[] { new BasicDBObject("$uplift", "$baseAvg") })); DBObject doc = new BasicDBObject("$baseAvg", 0); DBObject operation = new BasicDBObject("$project", new BasicDBObject(groupItem, "$_id." + groupItem) .append("mc", "$mc") .append("uplift", "$uplift") .append("baseAvg", "$baseAvg") .append("sumBaseUp", new BasicDBObject("$add", new DBObject[] {"$uplift", "$baseAvg"})) .append("share", new BasicDBObject("$cond", condArray)));

我得到这个结果:

{ "$project": { "dt": "$dt", "mc": "$mc", "uplift": "$uplift", "baseAvg": "$baseAvg", "sumBaseUp": { "$add": [{ "$uplift": "$baseAvg" }] }, "share": { "$cond": [{ "$eq": [{ "$baseAvg": 0 }] }, 0, { "$divide": [{ "$uplift": "$baseAvg" }] }] } } }

有人知道我应该怎么做吗?

Anybody knows what I should do?

推荐答案

您可以对Mongo Java 2.13版本使用以下聚合查询.我简化了一些操作.

You can use the below aggregation query for Mongo Java 2.13 version. I've simplified some operations.

List<DBObject> aggregates = Arrays.asList(new BasicDBObject("$project", new BasicDBObject("dt", "$dt"). append("mc", "$mc"). append("uplift", "$uplift"). append("baseAvg", "$baseAvg"). append("baseUp", new BasicDBObject("$add", Arrays.<Object>asList("$uplift", "$baseAvg"))). append("share", new BasicDBObject("$cond", Arrays.<Object>asList(new BasicDBObject("$eq", Arrays.<Object>asList("$baseAvg", 0)), 0, new BasicDBObject("$divide", Arrays.<Object>asList("$uplift", "$baseAvg")))))));

对于3.x版本，您可以使用以下汇总.

For 3.x version you can use below aggregation.

MongoClient mongoClient = new MongoClient(); MongoDatabase db = mongoClient.getDatabase("db"); MongoCollection<Document> collection = db.getCollection("collection"); Bson aggregates = Aggregates.project(Projections.fields(Projections.include("dt", "mc", "uplift","baseAvg"), new Document("baseUp", new Document("$add", Arrays.<Object>asList("$uplift", "$baseAvg"))), new Document("share", new Document("$cond", Arrays.<Object>asList(new Document("$eq", Arrays.<Object>asList("$baseAvg", 0)), 0, new Document("$divide", Arrays.<Object>asList("$uplift", "$baseAvg"))))))); List<Document> results = collection.aggregate(Arrays.asList(aggregates)).into(new ArrayList<>());