在MongoDB中的对象内插入数组

Question

我是MongoDB的新手,我想插入像这样的mongodb数据,但我无法弄清楚如何

{
  image = "cab"
  tags = [
            [ "NNP", 0 ],
            [ "NN", 1 ]
         ]
},
{
  image = "castle"
  tags = [
            [ "NNP", 2 ],
            [ "NN", 1 ],
         ]
}

我的代码是

    BasicDBObject obj = new BasicDBObject();
    obj.put("images", ....);
    for(Tag tag:tags){
    BasicDBObject tagsObj = new BasicDBObject();
    tagsObj.put("NNP",tag.getNNP());
    tagsObj.put("NN",tag.getNN());
    obj.put("tags",tagsObj);

    }

更新:使用此代码

Mongo m = new Mongo();
DB db = m.getDB("test");
DBCollection coll = db.getCollection("tags");
for(Tag tag:tags){
    BasicDBList dbl = new BasicDBList();
    dbl.add(new BasicDBObject("NNP",tag.getNNP()));
    dbl.add(new BasicDBObject("NN", tag.getNNP()));
    BasicDBObject outer=new BasicDBObject("images", currentImageName).append("tags", dbl);
    coll.insert(outer);
                }

我只存储每个图像,因为标签对于同一图像可能是这样的

  {
      image = "cab",
      tags = [
                { "NNP", 0 },
                { "NN", 1 }
             ],
             [  {"NNP", 4 },
                { "NN", 5 } 
             ],
             [
                {"NNP", 0 },
                { "NN", 4 }
             ]

},

谢谢

Answer 1

基本上,您将BasicDBObject用于键值映射,使用BasicDBList用于数组对象.对于您问题中的对象,您可以这样做:

BasicDBList dbl = new BasicDBList();
dbl.add(new BasicDBObject("NNP",0));
dbl.add(new BasicDBObject("NN", 1));
BasicDBOBject outer=new BasicDBObject("image", "cab").append("tags", dbl);

在api中有一些方便的方法可以使它更简洁一些.

映射的工作方式如下:

for:  {"A":1}  use: new BasicDBObject("A",1)
for: {"A":1, "B":2}  use: new BasicDBObject("A",1).append("B",2)
for: {"A":{"B":2}}  use: new BasicDBObject("A",new BasicDBObject("B",2))
for: {"A":["B","C"]} use:
        BasicDBList dbl = new BasicDBList();
        dbl.add("B");
        dbl.add("C");
         ->  new BasicDBObject("A",dbl);