POJO或DTO方法

Question

I am developing a new web application with Struts2, Spring and Hibernate as its core building blocks.

We have created POJO classes with respect to hibernate mapping files.There will be some inputs from users which needs to be updated in to the underlying database

eg registration or updation.

We have few option like creating new POJO/DTO for action classes which will be filled by the Struts2 and than we can transfer them to the service layer where we can convert those DTO to the respected hibernate POJO else we can expose same POJO to struts2 so that the framework can fill them with the user input and we need not to do the work for conversion and creating extra set of classes.

Application will be not big in size and will have a medium size application tag.

My question is what is the best way to transfer this user input to underlying hibernate layer to perform data base specific work.

Thanks in advance

Answer 1

I'd prefer the "DTO" approach in this case since you then can validate the input first and trigger updates only when wanted.

However, you could use detached entities as DTOs and reattach them when you want to create or update them. If you don't want the web part of your application to depend on Hibernate and/or JPA you might need to create another set of classes (unless you don't use a single annotation).

Answer 2

You'll get both answers on this.

With Struts 2 I tend to use normal S2 action properties to gather form values/etc. and use BeanUtils to copy them to the Hibernate objects. The problem with exposing the Hibernate objects to the form, like with ModelDriven etc. is that you need to define whitelists/blacklists if you have columns that should not be set directly by the user. (Or handle the problem in a different way.)

That said, I'm not fundamentally opposed to the idea like a lot of people are, and they're arguably correct.