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I'm currently writing my diploma thesis and I'm stuck at the Database Communication topic. My problem is not the implementation, but rather the architecture behind JSF. I read a lot about it, but don't really get it.

All my Database accesses are contained in the EJB project, and are handled with JDBC. JPA does the mapping between the DB-Entities and the Objects. So JDBC is just the driver which connects to the DB?

Thanks in advance!

daniiLein
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2 Answers2

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The architecture of the project must be well organized according to principle "low coupling and high cohesion"

The system layers should be well seperated. The basic architecture have 3 layers.

  1. Presentation Tier: JSF managed beans are in this layer. The task of this layer is to correspond user actions, hold user data and show the data to the user. Basically, its responsibility is bounded by MVC pattern regardless of which implementation you use (JSF, Spring MVC or Struts)
  2. Bussimess Logic Tier: The data and actions which was collected from page was sent to this layer to operate on data. You should not manipulte the data and prepare the response inside Presentation Tier. It is the responsibility of Bussiness Logic Tier.(Spring, CDI)
  3. Integration Tier: Database access should be done in this layer regardless of the library technology used (Hibernate, JPA, JDBC).

Sample Enterprise Java Architecture

As you can see in the pic. your JSF managed beans should only be capable of requests from the pages(controller) and page data (model). You can have a look to this answer to understand JSF MVC. Therefore, It is better to not to connect DB inside JSF managed beans. It is not a good practice.

The second part of your question. All technologies, Hibernate, JPA, Spring JDBC, uses JDBC driver of the related DB. JDBC Drivers is the just thing which connects to the DB. However, it is beter to select a method how to connect to DB, Hibernate, JPA or Spring JDBC.

You can download my example application which implements this architecture basically.

Community
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erencan
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  • Though your answer definitely contains a good overview of the issue, it is *not quite straight on terms*. Moreover, you are *mixing odd things* from time to time. It think your answer would benefit a lot in case you fixed those things. – skuntsel May 05 '13 at 19:48
  • what are those things? – erencan May 05 '13 at 19:51
  • 1. JSF managed beans *must not be bound* to the presentation tier. 2. CDI is a part of Java EE 6, and Spring (core) is a DI framework that *partially* complies with CDI specification. Moreover, CDI beans *can* be used as controllers, that is, be located in presentation tier, according to your overview. 3. JPA is an API, while Hibernate is *one of JPA implementations*. JPA and JDBC are *not libraries, but APIs*. The paragraph before the last one has everything mixed up. Finally, *some* web applications *can* use JDBC code in managed beans. – skuntsel May 05 '13 at 20:09
  • 1. JSF is not bound to presentation tier as i said not doing so "It is not a good practice". 2. I mentioned that you can use different MVC implementations such as struts or spring, the details are out of topic for the question" as CDI and Spring details are. 3. I mentioned Hibernate, JPA and others as technologies. I did not give details as it out of topic for the question. Finally, it is not a good practice to use JDBC code in managed beans. You are free to use whereever you want. – erencan May 05 '13 at 20:21
  • To repeat, *I think your answer is a good overview*, but for the sake of OP's understanding, I mentioned some inaccuracies, as I viewed them. – skuntsel May 05 '13 at 20:48
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JSF is in no way connected to database management, though the latter is typically always used in a JSF application.

Though all the job can be done with 'plain JDBC', it is more appropriately done using the Java Persistence API, or JPA. In the latter case, the JPA provider uses 'plain JDBC' under the covers.

Think of that relation in a following manner: (raw) JDBC is to JPA just like (raw) Servlet is to JSF.

skuntsel
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