Is Java for me?

[Tonatiuh]

I have this App:

BackEnd: Oracle 8i
FrontEnd: Visual Basic 6
Reports: Crystal Reports
Model: Client/Server (Two-Tier)

From VB code, I interact with Oracle Stored Procedures, and with the Crystal Reports, I can modify completely the reports at run-time.

From de VB code, I generate new Power Point, Excel and Word documents, and populate them with the data in the Oracle DB.

Actually I need to install the Oracle client and the FrontEnd in every PC client.

I want to translate all this functionality to a web app, so that I do not need to install anything in the PC client. I start from the fact that all PC clients have installed an internet browser (Iexplorer or Netscape) and Office, by default. I think I need to do it using the three-tier model.

Can I do all this with Java technologie? What Java courses will I need to take? What do you think about all this?

[hgroot]

I'll try to answer your question, though I am not very familiar with Oracle 8i or Crystal Reports.

Java has no standard interfaces to generate PowerPoint, Word or Excel documents. Maybe there are third party sources that do that, otherwise you'd have to write your own (in Java). You could choose to reuse parts of your VB code (legacy) to generate those formats.

Java has plenty of functionality to interact with databases, you probably will not need to change functionality of your existing database. You will need to reconfigure your server and write Java interfaces for database interaction.

If you want to develop a three-tier application, you'll have to have more advanced Java skills. Specially when you want to use a Java application server (for example J2EE).

Also, you'll have to understand HTTP/HTML/JSP/Servlets to write web applications.

I can't tell you what to do about those Crystal Reports. If it's a client-side application, you would also need to replace it with a web-interface. Otherwise, you would still have to install it on every PC.


I'd recommend this book if you're interested in learning Java, it's for beginners up to advanced developers:

"Complete Java 2 Certification Study Guide", Simon Robert - Philip Heller - Michael Ernest, Sybex press, ISBN 0-7821-2825-4.

This book also prepares you for Sun Certification Exams, so you can become a Sun Certified Programmer or Developer.

[Tonatiuh]

Thanks for your comments hgroot.

Could you explain more about Java Application Server?
What is it exactly?
Is there any other diferent from J2EE?

You mentioned that I need a third party tool to interact with Office products. Could you mention some tool?

[CaptainPinko]

every1 must be tired about hearing about java's independence, but that is one of its goals. Its meants to run anywhere and therefore it is very generalized. you want to interact w/ VERY specific apps w/ aren't too friendly, you could use java and then use NATIVE class OR you could code the **** out of the problem, since you don't really want OS indepence (since ur talking about Micro$oft products) just use VB and ActiveX just., it'll be a lot easier for you

[hgroot]

CaptainPinko is quite right, but a few explanations about Java won't hurt to have you make your own choices.

Indeed, next to J2EE, which is an application server by Sun, there also is Bea/Weblogic, or IBM WebSphere. They are all applications servers an all do the same thing, though there are differences between them so you can't just copy and reuse code on another server.

The application server is actually a webserver with a clear line between web logic, business logic and database logic (defined by interface classes). It is also a server on which you can deploy and undeploy applications without having to shut down or restart the server itself (maximum availability!). Code for an application server must comply with a strict interface and should only be developed by people with advanced OO skills.

I don't know about third party applications for MS file formats, sorry. There is a work-around, though I hesitate to suggest, but you can save documents in text-format. Excel can import CSV files (Comma Separated Values), Word can import RTF (Rich Text Format) and some earlier .DOC formats are also text-based. And as suggested before, you could write a Native interface for a legacy system, but that requires knowledge of C and functioning of the Java Virtual Machine.

Last, but not least, Do you *really* need to migrate to Java? You must expect to invest a lot of time and effort into it. Wouldn't it take less time to improve your VB code to achieve what you wanted with Java?

[Cudabean]

Here are some thoughts on what you are considering.

* Is it important to generate Excel/Powerpoint/Word documents? Or can other types of formats be substituted? An example might be to dynamically create a set of web pages instead of Powerpoint.

* Since your goal is to develop a web application, you need to be aware of some limitations. Programs running on the server (servlets, jsp's, etc.) have full capability to read and create files on the server, but due to security constraints client-side applets have no ability to read or write local client files. If you find that you need to do any client-side processing, you have the following choices:
1) Be content with not being able to read/write to/from local files
2) Go through the painful process of signing your applet which will allow it to read/write local files.
3) Write a client-side application that reads/writes local files BUT you have to install it on each computer.

* More on security: A user may upload a file to the server, but the user will be prompted for a file upload dialog for each file. The server can't just start grabbing files from the user's drive.

* Do you have a lot of users that make ad-hoc requests? Can the results of these requests be placed onto the server for the user to download? If the server creates some sort of file like a Powerpoint file or other format, it can download it to the user, but in order for the file to get to the user's local drive, the user must save it using a file dialog.

cudabean