Way to Prevent Duplicate Request from Form in J2EE applications - 3

To fix duplicate form submission issue, you essentially need to implement the Synchroniser Token pattern.

This Synchroniser Token pattern is a common technique as follows:

• Your application generates a unique token (based upon date, time and session id maybe) with each request or submits from the browser and embeds it in each HTML page returned to the browser as a hidden field.
• When the user hits a submit button, at the server you check that the token in the page matches the token on the server.
• If it does, you carry on.
• If it doesn't, you don't accept the submitted data (you either fail or just show the user the last page with an error/warning).
• Once the token is checked you immediately create a new unique token.

Now, if the same page is submitted again (by pressing the refresh button) or an old page is submitted (by the user pressing Back) the tokens will no longer match, as the server token was changed, so you can reject the submission.

-Happy Programming,

-NjN

Steps to enable SSL in Tomcat server

Tomcat SSL connection:

Refer the following web links to understand the details.

http://tomcat.apache.org/tomcat-6.0-doc/ssl-howto.html
http://www.globalsign.com/support/faq/tomcat/09.php

Tomcat Server - conf/server.xml file SSL settings & to generate a keystore, follow the steps mentioned in Tomcat support document.

For JBOSS application server lovers, it will be very similar to Tomcat.

-NJN

Web link for JSF specific updates

I can strongly recommend the link for JSF specific updates. Share your comments here!

Cheers

-NJN

Create your own JSF component in1.2 implementation

Have not tried your own JSF component in 1.2 version? Recommend you to have a look into below links to get to know about the component creation in JSF. After going through these links, I am sure you can able to create your own JSF component.

http://www.theserverside.com/news/1364786/Building-Custom-JSF-UI-Components

http://www.exadel.com/tutorial/jsf/HowToWriteYourOwnJSFComponents.pdf

http://www.ibm.com/developerworks/java/library/j-jsf4/

Cheers,

-NJN

Recommended website for J2EE framework website

This week, I was going through the recent J2EE technologies and framework updates from web. I was admired by seeing the website http://www.mkyong.com/ . It has very good J2EE framework updates for the experienced candidates who are keen to update their knowledgebase specifically in JSON, JSF2.0, Struts2.0 etc.

I am very happy and more delight to recommend the above mentioned information in my technical blog.

Happy reading!

Cheers,

-NJN

Create Bar code in Java based applications using BarCode4J

Guyz,

Today I have come across a requirement to print appointment confirmation letter with "Appointment Number" in a bar code format. I have goggled and come across a simple solution provided by BarCode4J. Generating different types of bar code is very simple using BarCode4J in java/j2ee applications. We strongly recommend you to go through the web link and explore the options available in BarCode4J. I strongly believe the sample application provided here are more than enough to understand the BarCode4J.

Hope this would be useful. Happy learning.

Cheers,
-NJN