我正在尝试使用Java驱动程序查询mongodb数据库中另一个文档中另一个文档中是否存在字段。我要求的字段是idMovie。

例如,如果idMovie为2,我希望它在控制台中显示“ idMovie值已经存在”。或如果idMovie为10,则打印“不存在”,因为文档中没有10

这是我的bson对象:

 { "_id" : { "$oid" : "5320aa3c3e468eaeb52dccdc"},
   "document" : "movies" ,
   "rateMovies" : [
        {
         "idMovie" : 2 ,
         "average" : "0" ,
         "sum" : "0" ,
         "total" : "0"
        } ,

       {
         "idMovie" : 3 ,
         "average" : "0" ,
         "sum" : "0" ,
         "total" : "0"
       }]
  }


这是我的Java代码:

MongoClient mongo = new MongoClient ("localhost", 27017);
        DB db = mongo.getDB("DBHC2");
        DBCollection movieDocument = db.getCollection("rateMovies");

        BasicDBObject searchQuery = new BasicDBObject();
        searchQuery.put("idMovie", idMovie);
        DBCursor cursor = movieDocument.find(searchQuery);

        /* if is true, the idMovie value already exist in database. */
        if(cursor.hasNext()){
            System.out.println("idMovie value already exist");
        }
        else{
            System.out.println("not exist");
        }


,但不适用于我。任何帮助都很好,谢谢!!

最佳答案

感谢您的帮助,但我自己找到了答案。

        MongoClient mongo = new MongoClient ("localhost", 27017);
        DB db = mongo.getDB("DBHC2");
        DBCollection movieDocument = db.getCollection("movies");

        BasicDBObject searchQuery = new BasicDBObject();
        searchQuery.put("rateMovies.idMovie", idMovie);
        DBCursor cursor = movieDocument.find(searchQuery);

07-27 17:36