3-Tier Architecture

Discussion in 'Java' started by Cris, Oct 22, 2003.

  1. Cris

    Cris Guest

    I'm relatively new to Java, having spent most of my time working with
    MS technologies. My company recently bought into J2EE/Unix (which we
    are all very excited about), and wants to begin the process of
    migrating our existing ASP/COM+ based web applications over to Java.
    Our existing web app architecture is as follows:

    * Web Server: ASP pages and COM+ proxy components
    * App Server: Core COM+ components containing business and DB logic
    * Database Server

    My question: Are EJBs the only way to duplicate this type of 3-tier
    environment when you're dealing with disparate servers like this? I've
    read that EJBs often tend to be overkill; however, I don't see how you
    can mimic this type of architecture with just JSPs, Servlets and
    standard Beans. Is there a proxy mechanism with Java, similar to COM+,
    where JSPs and Servlets running on the web server can remotely call
    beans on the app server?

    Any help is greatly appreciated.
    Cris, Oct 22, 2003
    #1
    1. Advertising

  2. Cris

    bm Guest

    Read this article from IBM see if it is helpful
    ftp://www6.software.ibm.com/software/developer/library/j-struts.pdf


    "Cris" <> wrote in message
    news:...
    > I'm relatively new to Java, having spent most of my time working with
    > MS technologies. My company recently bought into J2EE/Unix (which we
    > are all very excited about), and wants to begin the process of
    > migrating our existing ASP/COM+ based web applications over to Java.
    > Our existing web app architecture is as follows:
    >
    > * Web Server: ASP pages and COM+ proxy components
    > * App Server: Core COM+ components containing business and DB logic
    > * Database Server
    >
    > My question: Are EJBs the only way to duplicate this type of 3-tier
    > environment when you're dealing with disparate servers like this? I've
    > read that EJBs often tend to be overkill; however, I don't see how you
    > can mimic this type of architecture with just JSPs, Servlets and
    > standard Beans. Is there a proxy mechanism with Java, similar to COM+,
    > where JSPs and Servlets running on the web server can remotely call
    > beans on the app server?
    >
    > Any help is greatly appreciated.
    bm, Oct 22, 2003
    #2
    1. Advertising

  3. On 22 Oct 2003 14:35:57 -0700, Cris wrote:
    >environment when you're dealing with disparate servers like this? I've
    >read that EJBs often tend to be overkill; however, I don't see how you
    >can mimic this type of architecture with just JSPs, Servlets and
    >standard Beans. Is there a proxy mechanism with Java, similar to COM+,
    >where JSPs and Servlets running on the web server can remotely call
    >beans on the app server?
    >


    Hello,

    JDO seems a very good solution. I've recently developed with and it
    easy to use and yet powerful, especially compared to EJB, or JDBC
    with your own persistency management.
    See http://www.jdocentral.com
    Some JDO vendors provide remote persistencymanagers, for distributed
    environments, although you could combine it with EJB too.

    --
    Gerbrand van Dieijen
    Gerbrand van Dieijen, Oct 22, 2003
    #3
  4. Cris

    Cris Guest

    "bm" <> wrote in message news:<8WClb.1194$SJ1.834@edtnps84>...
    > Read this article from IBM see if it is helpful
    > ftp://www6.software.ibm.com/software/developer/library/j-struts.pdf
    >
    >
    > "Cris" <> wrote in message
    > news:...
    > > I'm relatively new to Java, having spent most of my time working with
    > > MS technologies. My company recently bought into J2EE/Unix (which we
    > > are all very excited about), and wants to begin the process of
    > > migrating our existing ASP/COM+ based web applications over to Java.
    > > Our existing web app architecture is as follows:
    > >
    > > * Web Server: ASP pages and COM+ proxy components
    > > * App Server: Core COM+ components containing business and DB logic
    > > * Database Server
    > >
    > > My question: Are EJBs the only way to duplicate this type of 3-tier
    > > environment when you're dealing with disparate servers like this? I've
    > > read that EJBs often tend to be overkill; however, I don't see how you
    > > can mimic this type of architecture with just JSPs, Servlets and
    > > standard Beans. Is there a proxy mechanism with Java, similar to COM+,
    > > where JSPs and Servlets running on the web server can remotely call
    > > beans on the app server?
    > >
    > > Any help is greatly appreciated.


    Thanks, both articles were very helpful; however, my question is more
    related to our existing server architecture and how Java might fit.

    My premature assumption on the subject is that there would be a
    servlet container running on the web server to service JSP and Servlet
    requests, and an EJB container running on the application server to
    service business and database logic component requests from the web
    server. Am I way off here? Is there an alternative to EJBs for
    remotely accessing business logic components from the web server?

    Forgive my ignorance; I'm fairly new to the Java world.
    Cris, Oct 23, 2003
    #4
  5. Cris

    bm Guest

    You've got the big picture right. To do architectural design,
    I believe you need to do a bit more studying. The three
    technologies that you'd be using are EJB, JSP and servlets.
    These books are very good.

    EJB Design Patterns, Wiely, Feb 2002, by Floyd Marinescu, ISBN:
    0-471-20831-0
    Server-Based Java Programming, Manning, July 2000, by Ted Neward
    - take a look at chapters 13 and 15
    EJB & JSP Java on the Edge, Wiely, Oct 2001, by Lou Marco, ISBN:
    0-764-54802-6

    good luck


    "Cris" <> wrote in message
    news:...
    > "bm" <> wrote in message

    news:<8WClb.1194$SJ1.834@edtnps84>...
    > > Read this article from IBM see if it is helpful
    > > ftp://www6.software.ibm.com/software/developer/library/j-struts.pdf
    > >
    > >
    > > "Cris" <> wrote in message
    > > news:...
    > > > I'm relatively new to Java, having spent most of my time working with
    > > > MS technologies. My company recently bought into J2EE/Unix (which we
    > > > are all very excited about), and wants to begin the process of
    > > > migrating our existing ASP/COM+ based web applications over to Java.
    > > > Our existing web app architecture is as follows:
    > > >
    > > > * Web Server: ASP pages and COM+ proxy components
    > > > * App Server: Core COM+ components containing business and DB logic
    > > > * Database Server
    > > >
    > > > My question: Are EJBs the only way to duplicate this type of 3-tier
    > > > environment when you're dealing with disparate servers like this? I've
    > > > read that EJBs often tend to be overkill; however, I don't see how you
    > > > can mimic this type of architecture with just JSPs, Servlets and
    > > > standard Beans. Is there a proxy mechanism with Java, similar to COM+,
    > > > where JSPs and Servlets running on the web server can remotely call
    > > > beans on the app server?
    > > >
    > > > Any help is greatly appreciated.

    >
    > Thanks, both articles were very helpful; however, my question is more
    > related to our existing server architecture and how Java might fit.
    >
    > My premature assumption on the subject is that there would be a
    > servlet container running on the web server to service JSP and Servlet
    > requests, and an EJB container running on the application server to
    > service business and database logic component requests from the web
    > server. Am I way off here? Is there an alternative to EJBs for
    > remotely accessing business logic components from the web server?
    >
    > Forgive my ignorance; I'm fairly new to the Java world.
    bm, Oct 23, 2003
    #5
  6. > My premature assumption on the subject is that there would be a
    > servlet container running on the web server to service JSP and Servlet
    > requests, and an EJB container running on the application server to
    > service business and database logic component requests from the web
    > server. Am I way off here?


    No, that's exactly the "traditional" J2EE three-tier architecture.

    > Is there an alternative to EJBs for
    > remotely accessing business logic components from the web server?


    There are certainly alternatives; you could simply run a custom
    Java application and have the web components contact it through RMI.
    It all depends on whether you think the abstractions and services
    provided by the EJB framework are worth the additional complexity.
    Michael Borgwardt, Oct 24, 2003
    #6
  7. Cris

    Anton Spaans Guest

    Hi Cris,

    This is what (in basic term) our product uses. It is a 3-tier J2EE
    application.

    -User communicates through HTTP with Front-End.
    Tier 1- Front-End running on Web Server. Web Server communicates with ...
    Tier 2- ... App Server through *stateless* EJB Session Beans. App Server
    communicates with ...
    Tier 3- ... Database through JDBC.

    We wrote the SQL our selves, combined with a simple type of JDO
    implementation (translating Java Objects into proper SQL statements). For
    performance reasons, we did not use EJB Entity Beans and used 'plain' JDBC
    instead.

    Hope this helps.


    "Cris" <> wrote in message
    news:...
    > I'm relatively new to Java, having spent most of my time working with
    > MS technologies. My company recently bought into J2EE/Unix (which we
    > are all very excited about), and wants to begin the process of
    > migrating our existing ASP/COM+ based web applications over to Java.
    > Our existing web app architecture is as follows:
    >
    > * Web Server: ASP pages and COM+ proxy components
    > * App Server: Core COM+ components containing business and DB logic
    > * Database Server
    >
    > My question: Are EJBs the only way to duplicate this type of 3-tier
    > environment when you're dealing with disparate servers like this? I've
    > read that EJBs often tend to be overkill; however, I don't see how you
    > can mimic this type of architecture with just JSPs, Servlets and
    > standard Beans. Is there a proxy mechanism with Java, similar to COM+,
    > where JSPs and Servlets running on the web server can remotely call
    > beans on the app server?
    >
    > Any help is greatly appreciated.
    Anton Spaans, Oct 27, 2003
    #7
  8. Cris

    Mike Guest

    You might check hibernate: www.hibernate.org
    Worth exploring as another Object/Relational mapping way than EJB.
    Simpler, Shorter, in good company with other impossible to ignore
    product: XDoclet, Velocity or even Middlegen at www.sourceforge.net
    Toplink, now at Oracle, www.oracle.com is also not completly to be
    thrown at the dogs. or should I say wolves (so close to Halloween).

    Mike

    "Anton Spaans" <aspaans at(noSPAM) smarttime dot(noSPAM) com> wrote in message news:<>...
    > Hi Cris,
    >
    > This is what (in basic term) our product uses. It is a 3-tier J2EE
    > application.
    >
    > -User communicates through HTTP with Front-End.
    > Tier 1- Front-End running on Web Server. Web Server communicates with ...
    > Tier 2- ... App Server through *stateless* EJB Session Beans. App Server
    > communicates with ...
    > Tier 3- ... Database through JDBC.
    >
    > We wrote the SQL our selves, combined with a simple type of JDO
    > implementation (translating Java Objects into proper SQL statements). For
    > performance reasons, we did not use EJB Entity Beans and used 'plain' JDBC
    > instead.
    >
    > Hope this helps.
    >
    >
    > "Cris" <> wrote in message
    > news:...
    > > I'm relatively new to Java, having spent most of my time working with
    > > MS technologies. My company recently bought into J2EE/Unix (which we
    > > are all very excited about), and wants to begin the process of
    > > migrating our existing ASP/COM+ based web applications over to Java.
    > > Our existing web app architecture is as follows:
    > >
    > > * Web Server: ASP pages and COM+ proxy components
    > > * App Server: Core COM+ components containing business and DB logic
    > > * Database Server
    > >
    > > My question: Are EJBs the only way to duplicate this type of 3-tier
    > > environment when you're dealing with disparate servers like this? I've
    > > read that EJBs often tend to be overkill; however, I don't see how you
    > > can mimic this type of architecture with just JSPs, Servlets and
    > > standard Beans. Is there a proxy mechanism with Java, similar to COM+,
    > > where JSPs and Servlets running on the web server can remotely call
    > > beans on the app server?
    > >
    > > Any help is greatly appreciated.
    Mike, Oct 30, 2003
    #8
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. rob

    ASP v2 & 3-tier or 2-tier

    rob, Aug 13, 2004, in forum: ASP .Net
    Replies:
    1
    Views:
    397
    Steve C. Orr [MVP, MCSD]
    Aug 13, 2004
  2. NOSPAM

    2 tier to 3 tier?

    NOSPAM, Oct 14, 2004, in forum: ASP .Net
    Replies:
    1
    Views:
    422
    =?Utf-8?B?Q293Ym95IChHcmVnb3J5IEEuIEJlYW1lcikgLSBN
    Oct 14, 2004
  3. Steve Kershaw

    Setting up a new tier in a 3-tier system?

    Steve Kershaw, Mar 28, 2006, in forum: ASP .Net
    Replies:
    3
    Views:
    436
    Steve Kershaw
    Mar 29, 2006
  4. Ebenezer
    Replies:
    2
    Views:
    917
    Ebenezer
    Nov 15, 2010
  5. Vin
    Replies:
    0
    Views:
    214
Loading...

Share This Page