Add sub document to mongodb with java

Question

It's the first time that I used mongodb and I added document from java in this way:

//document populated with for cycle
document.append(element.getID().toString(), new Document("EL_ID", feedback.getPos(i).getID())
                    .append("name", element.getName())
                    .append("vote", 5)
                );

//and write (replaceOne is correct for my program's logic)
BasicDBObject searchQuery = new BasicDBObject().append("_id", MainDocID);
collection.replaceOne(searchQuery, document);

the result is:

{
"_embedded": {},
"_links": { ... },
"_type": "DOCUMENT",
"_id": { ... },

"element_ID_1": {
    "EL_ID": {
        "$oid": "element_ID_1"
    },
    "name": "one",
    "vote": 5
},
"element_ID_2": {
    "EL_ID": {
        "$oid": "element_ID_2"
    },
    "name": "two",
    "vote": 5
},
"_created_on": "date"
}

I think it's correct to put these elements in "_embedded" and it's also more ordered, but I don't know how do this.

I want achieve this result:

{
    "_embedded": {

        "element_ID_1": {
          "EL_ID": {
            "$oid": "element_ID_1"
          },
          "name": "one",
          "vote": 5
        },

        "element_ID_2": {
          "EL_ID": {
            "$oid": "element_ID_2"
          },
          "name": "two",
          "vote": 5
        }
    },
      "_links": {},
      "_type": "DOCUMENT",
      "_id": {},
      "_created_on": "date"
}

or for example (same principle): _embedded -> elements_lista -> "element_ID_n"

I couldn't find an example applicable to my case (from java code), any suggestion is appreciate, thanks.

Answer 1

This needs to be handled in the way you are inserting the data into the Map.

Previously, you were setting the keys EL_ID, name and vote into the main Map. However you need to create a map say _embedded and keys mentioned above needs to be set into it.

When this overall DTO is inserted into the DB, it will be saved in a structure you have mentioned.

Answer 2

经过一些尝试，我已经解决了简单地创建一个包含所有元素的ArrayList并将其附加到文档中的字符串键“_embedded”