Exposing DAO as web service

Question

Hello,

Can anyone point me in the direction of documentation for exposing a DAO as an external web service? Currently, in my application we follow a DAO -> Service -> UI layered architecture. Everything is internal to the app, our DAOs access the DB through Spring JDBC and the services are visible only to the web application.

We now have a need for downstream systems within my company to access the DAOs we've created. I need to know what the effort would be to expose our DAOs and what, if any, other technologies I would need to perform this task.

Also, would I expose the DAOs themselves or the services?

Answer 1

I guess I don't fully understand the problem. You'll have to create service operations that do CRUD operations for you DAOs, along with operations for any special data processing your DAOs perform. You already expose the DAOs via service to your current UI. Can you not simply use that service as a template for your externally facing service?

Answer 2

Well, I would suggest not to expose DAO through WebServices,Instead expose Service method in WS.

But if you need to do this

Create a Layer of WebServices right above of DAO and lower the Core Service Layer.

And you can expose DAO to any other modules if you want.

Let me know why DAO is needed to be exposed.

Answer 3

If I were you, I'll just wrap the DAOs in a webservice. So, first define the wsdl, then generate the java code that goes with that wsdl. Then, in the webservice implementation, just hand-copy the entity beans into this webservice beans. Guess you could use bean copy utils if that is too tedious.

Not sure if you can use the entity beans directly in java2wsdl style webservice development, but that seems like a bad idea because you don't have an abstraction layer between entity beans and webservice interface in that case.