Mongodb擷取附近的人

double[] loc = new double[2];//座標[longitude, latitude]loc[0] = 114d;//longitudeloc[1] = 118d;// latitudeDBObject near = new BasicDBObject();near.put("$near", loc);//表示near查詢,單位是“度”near.put("$maxDistance",  <distance in meters>);//最大距離near.put("$minDistance", <distance in meters>);//最小距離DBObject p = new BasicDBObject();p.put(“loc”, near);//座標在collection中的欄位名,你這是locDBCollection dbCollection = positionDB.getCollection(“places”);//擷取資料庫裡的collection,你這是placesDBCursor dbCursor = dbCollection.find(dbObject).limit(20);//尋找20個