java - 从 mongodb 的 JSON 字段中提取字段

Question

我想提取“位置”字段中提到的所有这些位置，并且不想要下面 json 中的其他字段。但由于它是嵌套的，所以无法提取。有人可以帮助我吗？

    DBCursor cursorTotal = coll.find(obje);

    while (cursorTotal.hasNext()) {

        DBObject curNext = cursorTotal.next();

        System.out.println("data::"+curNext.get("list.myList.location");
   }

我的“curNext”给出的输出为::

    {
    "_id": {
    "$oid": "51ebe983e4b0d529b4df2a0e"
    },
    "date": {
    "$date": "2013-07-21T13:31:11.000Z"
    },
    "lTitle": "Three held for running CISF job racket",
    "list": {
    "myList": [
        {
            "location": "Germany"
        },
        {
            "location": "Geneva"
        },
        {
            "location": "Paris"
        }
    ]
    },
    "hash": -1535814113,
    "category": "news"
}

我希望我的输出为

Germany,Geneva,Paris

Answer 1

我在这里等待答案很长时间，终于得到了我正在寻找的东西......只是记下我的答案，以便其他人可以从中受益

  DBCursor cursorTotal = coll.find(obje);

    while (cursorTotal.hasNext()) {

    DBObject curNext = cursorTotal.next();

            String res=curNext.toString();
           JsonElement jelement = new JsonParser().parse(res);
            JsonObject  jobject = jelement.getAsJsonObject();
            jobject = jobject.getAsJsonObject("list");
            JsonArray jarray = jobject.getAsJsonArray("myList");
            jobject = jarray.get(0).getAsJsonObject();
            String result = jobject.get("location").getAsString();


            System.out.println("all places::"+result);
}