Hi,

I'm using Hibernate 3.1.3 and using JSP for development.

I read from some hibernate examples that we should put persistence related coding in DAO classes.

I'm designing a search page where user can enter one or multiple search criteria values. For example, user can search by title, or author, or subject or isbn or combination of these.

Let say I have a Book class (the POJO) and a BookDAO class. I know my BookDAO will need a method call searchBook. My doubt starts here.

I need some coding that dynamically determine what search criteria was entered by user then construct the required conditions for selecting from the class. Should I put this coding inside the BookDAO's searchBook method or I just code it in the JSP ?

If put the code in BookDAO, that means I have to fix the method to accept various parameters. But these parameters might be different based on the search criteria that the user has entered. Most of the example and reference book I read have their method accept specific parameters only, which I think I can apply in my case.

If put the code in JSP, then we will have hibernate persistence coding inside JSP? Do most of you put hibernate related coding in JSP as well? Another concern is i afraid these code in JSP will be expose to others especially if we are building a product and deploy at a customer side.

So, should I put in JSP or DAO. If put in DAO, how we usually make the method that select from class to accept dynamic condition, different order by and group by clause.

Please advise.
Thank you.

Hi,

as a rule of thumb you should never put code into jsp pages, this is a maintenance nightmare in the long run. You should apply the MVC (model-view-controller) design pattern. Use Jsp pages only to render the informations, put all the java code in a separate class which constructs DAO objects and there issue the database queries. The results are then bound to the request, or session object (request.setAttribure("results", resultlist)) and can be accessed by the jsp.

Hope this helps,

Axel

Using MVC, you will need a Model object. That will in turn call the DAO. If the number of parameters might vary and there might be a possibility of adding or subtracting choices, DAO take a single class as a parameter called something like SearchParametersBean. The model will make one of these and fill it depending on options supplied by the user. This gets passed to the DAO.

You should also consider a Controller framework such as Struts or Spring MVC to controlling the JSP. Spring also has a lightweight framework to handle the creation of the Model and the DAO.

NEVER EVER PUT CODE IN YOUR JSP. Very bad coding practice.

You can always capture as to what is the search criteria that the user has entered in the screen. You can use Struts to control ur JSPs or pass it on as sesion objects, capture them in the underlying layer and call the respective queries in the DAO layer.

Hi,

Just to add. Our other posters are right about going to MVC.

For dynamic search, you should use the Criteria of Hibernate. This will make your job simple for the search condition and parameters.

Criteria will construt the Query on the runtime based on the values you have entered in the JSP. Read the below link to know more about Criteria.

http://www.hibernate.org/hib_docs/v3/re ... rycriteria

All the Best