How to retrive data in array format mongoDb SpringBoot

Question

I have datas in my mongoDB as follow

{
    "stack":"webTechnology",
    "subStack":"angular"
},
{
    "stack":"webTechnology",
    "subStack":"react"
}.
{
    "stack":"webTechnology",
    "subStack":"angular"
},
{
    "stack":"script",
    "subStack":"python"
},
{
    "stack":"script",
    "subStack":"javaScript"
},
{
    "stack":"Java",
    "subStack":"Spring"
}

I need to return these data as response from Rest API in the following format, Categorized by stack and substack

[
    "webTechnology":[
        "angular":[
            {
                "stack":"webTechnology",
                "subStack":"angular"
            },
            {
                "stack":"webTechnology",
                "subStack":"angular"
            }
        ],
        "react":[
            {
                "stack":"webTechnology",
                "subStack":"react"
            }
        ]
    ],
    "script":[
        "python":[
            {
                "stack":"script",
                "subStack":"python"
            }
        ],
        "javaScript":[
            {
                "stack":"script",
                "subStack":"javaScript"
            }
        ]
    ],
    "java":[
        "spring":[
            {
                "stack":"java",
                "subStack":"spring"
            }
        ]
    ]
]

Im using mongoTemplate to retrieve the data, which is returning in the List format

mongoTemplate.getCollection(collectionName).find().toArray()

How can I get the result in the way which Im expecting?

Are you using groovy or java?

dsharew
– dsharew

2018-03-19 06:48:55 +00:00
Commented Mar 19, 2018 at 6:48 — dsharew
– dsharew, Commented Mar 19, 2018 at 6:48

dsharew · Accepted Answer · 2018-03-19 06:51:53Z

1

I inserted your data into a temp collection dataCollection and here is the query for grouping the data by stack and substack:

db.getCollection('dataCollection').aggregate([

    {

          $group: {
                _id: {stack: "$stack", subStack: "$subStack"},
                result: { $push : "$$ROOT" }

              }

    }

])

It should not be hard to convert the query to mongotemplate format; let me know if you have issues.

Output:

/* 1 */
{
    "_id" : {
        "stack" : "Java",
        "subStack" : "Spring"
    },
    "result" : [ 
        {
            "_id" : ObjectId("5aaf5b65f2046e3bf671328a"),
            "stack" : "Java",
            "subStack" : "Spring"
        }
    ]
}

/* 2 */
{
    "_id" : {
        "stack" : "webTechnology",
        "subStack" : "angular"
    },
    "result" : [ 
        {
            "_id" : ObjectId("5aaf5b65f2046e3bf6713285"),
            "stack" : "webTechnology",
            "subStack" : "angular"
        }, 
        {
            "_id" : ObjectId("5aaf5b65f2046e3bf6713287"),
            "stack" : "webTechnology",
            "subStack" : "angular"
        }
    ]
}

/* 3 */
{
    "_id" : {
        "stack" : "script",
        "subStack" : "python"
    },
    "result" : [ 
        {
            "_id" : ObjectId("5aaf5b65f2046e3bf6713288"),
            "stack" : "script",
            "subStack" : "python"
        }
    ]
}

/* 4 */
{
    "_id" : {
        "stack" : "webTechnology",
        "subStack" : "react"
    },
    "result" : [ 
        {
            "_id" : ObjectId("5aaf5b65f2046e3bf6713286"),
            "stack" : "webTechnology",
            "subStack" : "react"
        }
    ]
}

/* 5 */
{
    "_id" : {
        "stack" : "script",
        "subStack" : "javaScript"
    },
    "result" : [ 
        {
            "_id" : ObjectId("5aaf5b65f2046e3bf6713289"),
            "stack" : "script",
            "subStack" : "javaScript"
        }
    ]
}

answered Mar 19, 2018 at 6:51

dsharew

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1 Comment

Nithyananth Over a year ago

I have formed the query and it gives the result as expected. Thanks @dsharew. Can someone help me on how to send this through ResponseEntity from REST API,

DBObject query = new BasicDBObject("$group", 				new BasicDBObject("_id", new BasicDBObject("stack", "$stack").append("subStack", "$subStack")) 						.append("result", new BasicDBObject("$push", "$$ROOT"))); 		AggregationOutput output = mongoTemplate.getCollection("contributionInfoBean").aggregate(query);

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