How can I sort and get a list in complex collection mongodb in java?

Question

This is my dbcollection in mongodb

{
    "_id" : 0,
    "name" : "+Anima",
    "author" : "MUKAI Natsumi",
    "type" : [ 
        "Adventure", 
        "Fantasy"
    ],
    "chapters" : [ 
        {
            "chapterName" : "+Anima 56",
            "chapterLink" : "http://...",
            "groupTranslate" : "Manga Palace Group",
            "dateUpload" : 1359478800000,
            "chapterNumber" : 56.0000000000000000,
            "images" : [ 
                 "img0", 
                "img1", 
                "img2", 
                "img3"
            ]
        }, 
        {
            "chapterName" : "+Anima 55",
            "chapterLink" : "http://....",
            "groupTranslate" : "Manga Palace Group",
            "dateUpload" : 1410109200000,
            "chapterNumber" : 55.0000000000000000,
            "images" : [ 
                "img0", 
                "img1", 
                "img2", 
                "img3"
            ]
        }
    ]
}

I cannot find list chapter sort by "dateUpload" in mongodb using java code. Please help.

You want only chapters list sorted order according to dateUpload is right? — Neo-coder
– Neo-coder, Commented Mar 29, 2015 at 10:24

Neo-coder · Accepted Answer · 2015-03-29 10:51:37Z

2

Mongo $aggregation will solve your problem. Below query first $unwind your chapters array and then sort dateUpload

    db.collectionName.aggregate({
    "$unwind": "$chapters" // unwind breaks the chapters array
}, {
    "$sort": {
    "chapters.dateUpload": -1 // then seperated chapters array sorted by dateUpload
    }
}, {
    "$group": {
    "_id": "$_id",
    "chapters": {
        "$push": "$chapters" // group used for grouping chapters array
    }
    }
}).pretty()

And for converting above query in java code formatt then follow below mongo aggregation java driver code . Java Driver and Aggregation Framework

answered Mar 29, 2015 at 10:51

Neo-coder

7,8585 gold badges36 silver badges54 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

guido · Accepted Answer · 2015-03-29 10:41:38Z

0

This should do it, using aggregate():

db.foo.aggregate( [ { $project: {chapters: 1} },
                    { $unwind: "$chapters" },
                    { $sort: {"chapters.dateUpload": -1} }
                  ] );

Extract the chapters subdocument with $project, then $unwind it to deconstruct the array and get each element, finally $sort them on dateUpload value (descending, use 1 for ascending order).

edited Mar 29, 2015 at 10:41

answered Mar 29, 2015 at 10:32

guido

19.3k6 gold badges74 silver badges97 bronze badges

Collectives™ on Stack Overflow

How can I sort and get a list in complex collection mongodb in java?

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related