将Mongo聚合查询转换为java对象

我正在尝试将mongo聚合查询转换为java对象。当我在RoboMongo（工具）中运行查询时，我会得到结果，但转换为java对象会得到空结果

Mongo查询：

db.getCollection('wb_physicians').aggregate([
    { 
        $match: { 
            $and: [ 
                { "product.mpoCode": "VA001"}, 
                { "product.npoCode": { $exists: true } }
            ] 
        }
    },
    { 
        "$project" : { 
            "product.specialties.code": 1, 
            "providerId": 1,
            "product.code": 1, 
            "_id" : 0
        }
    }, 
    { "$unwind" : "$product.specialties" },
    { 
        "$group" : { 
            "_id" : { 
                "providerId": "$providerId" , 
                "productCode": "$product.code"
            }, 
            "specialityCodeList": { "$addToSet": "$product.specialties.code" }
        }
    }
])

private static AggregationOutput findProviderandSpecialty(DBCollection collection) {
    DBObject match =  new BasicDBObject("$match" , 
        new BasicDBObject("$and", Arrays.asList(
            new BasicDBObject("product.mpoCode" , "VA001").append("product.npoCode", "$exists: true")
        ))
    );

    DBObject project =  new BasicDBObject("$project" , 
        new BasicDBObject("product.specialties.code" , 1)
            .append("providerId" , 1)
            .append("product.code", 1)
            .append("_id", 0)
    );  

    DBObject unwind = new BasicDBObject("$unwind" , "$product.specialties");

    DBObject group = new BasicDBObject("$group",
        new BasicDBObject("_id", new BasicDBObject("providerId" , "$providerId"))
            .append("specialityCodeList", 
                new BasicDBObject("$addToSet", "$product.specialties.code")
            )
    );

    AggregationOutput output = collection.aggregate(match,project,unwind,group);    

    return output;
}   

Java代码：

db.getCollection('wb_physicians').aggregate([
    { 
        $match: { 
            $and: [ 
                { "product.mpoCode": "VA001"}, 
                { "product.npoCode": { $exists: true } }
            ] 
        }
    },
    { 
        "$project" : { 
            "product.specialties.code": 1, 
            "providerId": 1,
            "product.code": 1, 
            "_id" : 0
        }
    }, 
    { "$unwind" : "$product.specialties" },
    { 
        "$group" : { 
            "_id" : { 
                "providerId": "$providerId" , 
                "productCode": "$product.code"
            }, 
            "specialityCodeList": { "$addToSet": "$product.specialties.code" }
        }
    }
])

private static AggregationOutput findProviderandSpecialty(DBCollection collection) {
    DBObject match =  new BasicDBObject("$match" , 
        new BasicDBObject("$and", Arrays.asList(
            new BasicDBObject("product.mpoCode" , "VA001").append("product.npoCode", "$exists: true")
        ))
    );

    DBObject project =  new BasicDBObject("$project" , 
        new BasicDBObject("product.specialties.code" , 1)
            .append("providerId" , 1)
            .append("product.code", 1)
            .append("_id", 0)
    );  

    DBObject unwind = new BasicDBObject("$unwind" , "$product.specialties");

    DBObject group = new BasicDBObject("$group",
        new BasicDBObject("_id", new BasicDBObject("providerId" , "$providerId"))
            .append("specialityCodeList", 
                new BasicDBObject("$addToSet", "$product.specialties.code")
            )
    );

    AggregationOutput output = collection.aggregate(match,project,unwind,group);    

    return output;
}   

您能帮助我在哪里做了错误的映射吗？

问题正在解决中：

DBObject match =  new BasicDBObject("$match" , 
    new BasicDBObject("$and", Arrays.asList(
        new BasicDBObject("product.mpoCode" , "VA001")
           .append("product.npoCode", "$exists: true")
    ))
);

应该是

DBObject match =  new BasicDBObject("$match" , 
    new BasicDBObject("$and", Arrays.asList(
        new BasicDBObject("product.mpoCode" , "VA001"),
        new BasicDBObject("product.npoCode", 
            new BasicDBObject("$exists", "true")
        )
    ))
);

---

尽管如此，通过指定文档的逗号分隔表达式以及删除之前的管道，您可以不使用显式逻辑 因为这是相当不必要的，所以您修改后的管道可以按以下方式运行：

db.getCollection('wb_physicians').aggregate([
    { 
        "$match": { 
            "product.mpoCode": "VA001", 
            "product.npoCode": { "$exists": true }             
        }
    },    
    { "$unwind" : "$product.specialties" },
    { 
        "$group" : { 
            "_id" : { 
                "providerId": "$providerId" , 
                "productCode": "$product.code"
            }, 
            "specialityCodeList": { "$addToSet": "$product.specialties.code" }
        }
    }
])

最后的Java代码是：

private static AggregationOutput findProviderandSpecialty(DBCollection collection) {
    DBObject match =  new BasicDBObject("$match" , 
        new BasicDBObject("product.mpoCode" , "VA001").append("product.npoCode",             
            new BasicDBObject("$exists", "true")
        )        
    );

    DBObject unwind = new BasicDBObject("$unwind" , "$product.specialties");

    DBObject group = new BasicDBObject("$group",
        new BasicDBObject("_id", new BasicDBObject("providerId" , "$providerId"))
            .append("specialityCodeList", 
                new BasicDBObject("$addToSet", "$product.specialties.code")
            )
    );

    List<DBObject> pipeline = Arrays.<DBObject>asList(match, unwind, group);
    AggregationOutput output = collection.aggregate(pipeline);    

    return output;
}   

私有静态聚合输出FindProviderAndSpeciality（DBCollection集合）{
DBObject match=新的基本对象（$match），
新的BasicDBObject（“product.mpoCode”、“VA001”）.append（“product.npoCode”，
新的BasicDBObject（“$exists”，“true”）
)        
);
DBObject unwind=newBasicDBObject（“$unwind”，“$product.specialties”）；
DBObject group=新的BasicDBObject（$group），
新的BasicDBObject（“\u id”，新的BasicDBObject（“providerId”，“$providerId”））
.append（“specialityCodeList”，
新的BasicDBObject（$addToSet，“$product.specialties.code”）
)
);
列表管道=Arrays.asList（匹配、展开、组）；
AggregationOutput输出=collection.aggregate（管道）；
返回输出；
}   

+1，以清楚地显示您正在尝试做什么以及您迄今为止已经尝试了什么；并说明出错的原因。感谢您的回答。我得到了结果。当我尝试迭代聚合输出时，为（DBObject ldocFromDB:cursorDoc.results（））的“providerId”获取null poniter（{DBObject providerId=（DBObject）ldocFromDB.get（PROVIDER_ID）；BasicDBList specialtyList=（BasicDBList）ldocFromDB.get（“specialityCodeList”)}但是得到了基本列表值的结果。你能帮我获取DBObject值吗。这是输出“_id”：{“providerId”：“3310100”，“productCode”：“CONNECT”}，“specialityCodeList”：[“OP”]}看起来已经解决了，不是吗？至于另一个问题，那将是A，考虑分开发布。