Mongodb Java - 如何使用 find() 或 findOne() 返回受限字段
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Mongodb Java - How to return restricted fields with find() or findOne()
提问by kozher
With the driver Java Mongodb, I am looking for a way to return just restricted fields with a
find()or findOne().
For example, I have a collection "people"with fields : "id", "name", "surname", "address", "city"... and I just want to return "name"and "surname"
使用驱动程序 Java Mongodb，我正在寻找一种方法来仅返回带有find()或的受限字段
findOne()。例如，我有一个"people"包含字段的集合："id", "name", "surname", "address", "city"... 我只想返回"name"和"surname"
I searched on the Web and I just found this example of code Java Mongodb : http://vsbabu.org/mt/archives/2010/03/02/simple_mongodbjava_example.html
我在网上搜索，我刚刚找到了这个 Java Mongodb 代码示例：http://vsbabu.org/mt/archives/2010/03/02/simple_mongodbjava_example.html
采纳答案by lobster1234
You can pass another DBObject with the names of the fields and pass it here:
您可以传递另一个带有字段名称的 DBObject 并在此处传递：
cur = coll.find(new BasicDBObject("id", 6655), your_dbobject_with_field_names);
Here is the API documentation
这是API 文档
回答by seb
If you are using Java Driver 3.1, you can use Projections:
如果您使用的是 Java Driver 3.1，则可以使用Projections：
collection.find().projection(Projections.include("name", "surname"));
回答by G?khan Ayhan
This codes will handle your problem.(java driver 3.0.2)
此代码将处理您的问题。（java 驱动程序 3.0.2）
BasicDBObject fields = new BasicDBObject();
fields.put("title", 1);
DBCursor cursor = collection.find(new BasicDBObject(),fields).sort(new BasicDBObject("_id", 1));
回答by HungNM2
this code run for me:
这段代码为我运行：
String json = "{_id:0,name:1,surname:1}";
Bson bson = BasicDBObject.parse( json );
FindIterable<Document> iterDoc = collection.find().projection(bson);
