Java code for mongodb aggregation query with $in

问题

I am new to mongodb and need an equivalent code in java for the below

db.asset.aggregate([{
            $unwind : '$asset'
        }, {
            $match : {
                'asset.status' : {
                    $in : ['1', '2', '3']
                },
                'asset.siteid' : {
                    $in : ['123']
                }
            }
        }
    ]).pretty()

I tried the following but it didn't help-out

    DBObject unwind = new BasicDBObject("$unwind", "$dp.asset");
    DBObject match  = BasicDBObjectBuilder.start().push("$match")
                  .push("dp.asset.status").add("$in", ['ACTIVE', 'LIMITEDUSE', 'OPERATING'])
                  .push("dp.asset.siteid").add("$in", ['BEDFORD']).get();

    AggregationOutput aggr = collection.aggregate(Arrays.asList(unwind, match));

Note : i am using mongodb 3.4.1

回答1:

Not sure why you are using single quotes while passing the array value.

The right syntax to pass the values are

 DBObject match  = BasicDBObjectBuilder.start().push("$match")
             .push("$dp.asset.status").add("$in", Arrays.asList("ACTIVE", "LIMITEDUSE", "OPERATING"))
             .push("$dp.asset.siteid").add("$in", Arrays.asList("BEDFORD")).get();

Or

DBObject match  = BasicDBObjectBuilder.start().push("$match")
             .push("$dp.asset.status").add("$in", new String[]{"ACTIVE", "LIMITEDUSE", "OPERATING"})
             .push("$dp.asset.siteid").add("$in", new String[]{"BEDFORD"}).get();

For 3.x drivers, you should be using Document.

Document unwind = new Document("$unwind", "$dp.asset");
Document match  = new Document("$match", new Document("$dp.asset.status", new Document("$in", new String[]{"ACTIVE", "LIMITEDUSE", "OPERATING"})).
             append("$dp.asset.siteid", new Document("$in", new String[]{"BEDFORD"})));

Code for Mongo Query.

 Document unwind = new Document("$unwind", "$asset");
 Document match  = new Document("$match", new Document("$asset.status", new Document("$in", new String[]{"1", "2", "3"})).
         append("$asset.siteid", new Document("$in", new String[]{"123"})));

回答2:

The fields in your mongo shell aggregation operation do not match with the ones in the current Java pipeline.

Apart from that anomaly, you could try the following pipeline:

BasicDBList statusList = new BasicDBList();
statusList.add("1");
statusList.add("2");
statusList.add("3");
DBObject statusInClause = new BasicDBObject("$in", statusList);  

BasicDBList idList = new BasicDBList();
idList.add("123");
DBObject siteIdInClause = new BasicDBObject("$in", idList); 

DBObject fields = new BasicDBObject("asset.status", statusInClause);
fields.put("asset.siteid", siteIdInClause);

DBObject unwind = new BasicDBObject("$unwind", "$asset");
DBObject match = new BasicDBObject("$match", fields); 

AggregationOutput aggr = collection.aggregate(Arrays.asList(unwind, match));

来源：https://stackoverflow.com/questions/41377962/java-code-for-mongodb-aggregation-query-with-in