public void insertCenterUser(CenterUser user) {
coll.insert(BasicDBObjectBuilder.start(user.toMap()).get());
}
public void updateCenterUser(CenterUser user) {
DBObject obj = coll.findOne(new ObjectId(user.getId()), null);
coll.update(obj, BasicDBObjectBuilder.start(user.toMap()).get(), true, false);
}