如何从 Java mongodb 中的 BasicDBList 创建 List<String>？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/23578637/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to create a List<String> from a BasicDBList in mongodb in Java?
提问by khirod
The JSON stored in mongodb database is of form
mongodb 数据库中存储的 JSON 格式为
{
"genre": ["Action", "Animation", "Drama"],
"movie_id": 1
}
I have to get a list of genres. Sorry if the question is lame. I'm kinda new to Java and mongodb.
我必须得到一个流派列表。对不起，如果问题是蹩脚的。我对 Java 和 mongodb 有点陌生。
采纳答案by jmen7070
i propose the below code to solve your issue:
我建议使用以下代码来解决您的问题：
MongoClient mongo = new MongoClient( "localhost" , 27017 );
DB db = mongo.getDB(dbName);
DBCollection collection = db.getCollection(collectionName);
BasicDBObject whereQuery = new BasicDBObject();
whereQuery.put("movie_id", id);
DBObject document = collection.findOne(whereQuery);
BasicDBList list = (BasicDBList) document.get("genre");
List<String> res = new ArrayList<String>();
for(Object el: list) {
res.add((String) el);
}
回答by user2791631
DBObject channelDBObject = new BasicDBObject();
System.out.println("genre");
String genre = bufferReader.readLine();
String[] temp = genre.split(",");
int i=0;
BasicDBList genreDBList = new BasicDBList();
DBObject genreDBObject = null;
while(i<temp.length){
genreDBObject = new BasicDBObject();
genreDBObject.put("genre",temp[i++]);
genreDBList.add(genreDBObject);
}
channelDBObject.put("genre",genreDBList.toArray());
System.out.println("Movie Id");
String MovieId = bufferReader.readLine();
channelDBObject.put("MovieId",Integer.parseInt(MovieId));
dBCollection.insert(channelDBObject);
DBCursor dbcursor = dBCollection.find();
while (dbcursor.hasNext())System.out.println(dbcursor.next());
}
回答by Alberto Cerqueira
Look:
看：
{
"genre": ["Action", "Animation", "Drama"],
"movie_id": 1,
"attributes" : [
{
"name" : "name 1",
"value" : "value 1"
}, {
"name" : "name 2",
"value" : "value 2"
}
]
}
You can use:
您可以使用：
DBObject dbObject = (DBObject) object.get("attributes");
BasicDBList list = new BasicDBList();
for (String key : dbObject.keySet()) {
list.add(dbObject.get(key));
}
List<String> listArray = new ArrayList<String>();
for (Object object : list) {
listArray.add(object.toString());
}
and
和
DBObject dbObject = (DBObject) object.get("genre");
List<String> listArray = new ArrayList<String>();
for (String key : dbObject.keySet()) {
list.add(((DBObject) dbObject.get(key)).toString());
}
You can too (but, maybe don't working):
你也可以（但是，也许不工作）：
BasicDBList list = (BasicDBList) object.get("attributes");
List<String> listArray = new ArrayList<String>();
for (Object object : list) {
listArray.add(((DBObject) object).toString());
}
and
和
BasicDBList list = (BasicDBList) object.get("genre");
List<String> listArray = new ArrayList<String>();
for (Object object : list) {
listArray.add(object.toString());
}
