Java - Saving Objects Using DBObject

The Java driver provides a DBObject interface to save custom objects to the database.

For example, suppose one had a class called Tweet that they wanted to save:

public class Tweet implements DBObject {
    /* ... */
}

Then you can say:

Tweet myTweet = new Tweet();
myTweet.put("user", userId);
myTweet.put("message", msg);
myTweet.put("date", new Date());

collection.insert(myTweet);

When a document is retrieved from the database, it is automatically converted to a DBObject. To convert it to an instance of your class, use DBCollection.setObjectClass():

collection.setObjectClass(Tweet.class);

Tweet myTweet = (Tweet)collection.findOne();

If for some reason you wanted to change the message you can simply take that tweet and save it back after updating the field.

Tweet myTweet = (Tweet)collection.findOne();
myTweet.put("message", newMsg);

collection.save(myTweet);