First of all, DTO and Data file means the same thing.
Model is something which is generated on build. An entry of the attribute/item is done in xml file, build is done and Model file is created. It has all the attribute defined with their setters and getters.
DTO/data file(also known as pojo file in some cultures :P) is something created manually by the user. It also has attributes defined with their setters and getters.
Model is generally used to update the database with the values. DTO/data is used to transfer object values b/w controller to jsp or between various layers(controller, facade, service etc). I reason being that DTO/data are generally considered as “lighter” components comapared to models. The latter thus is used for only updation of database rather than general passing of the data between files.