Archive for May, 2010

Reading rss feed using java (JSP Taglib)

We can read RSS (Real Simple Syndication) feeds and publish them on our web page using JSP(Java Server Pages) tag library. Sun provides a rss taglib that can be used in JSP. It is extremely simple to use. You just need to have basic knowledge of JSP and HTML.

So, how to do that? First you need to download the tag library file (rssutils.tld, rssutils.jar) from Sun’s website. Here is the url to download it. Put the files rssutils.tld and rssutils.jar in WEB-INF/lib directory of your web application.
After that, choose a blog or website who publishes its rss feeds to users, and get the url of its rss feed. In below example, I have used the rss feed url of this blog. Please find the attached file here and save it with .jsp extension (rssTest.jsp)
You can use tag also to read content in a loop.
For a small tutorial on rss taglib, go here

To know what RSS is, go here

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2 Comments

enum as a class

Here I have compared enum with a class. In java, enums are like classes. What I have done here is, if we have to write a class that works like en enum, how can we do it. Though it is not of practicle use,what I have tried is to make the concept clear about enums.By comparing enum with a class, we can understand how enums work.

Here DayEnum is a enum and DayClass is class for that enum.

enum DayEnum {
SUNDAY, MONDAY
}

class DayClass {
String value;
public DayClass (String str)
{
value=str;
}

static DayClass SUNDAY, MONDAY;
static
{
SUNDAY = new DayClass("SUNDAY");
MONDAY = new DayClass("MONDAY");
}
}

public class Test
{
public static void main(String args[])
{
DayClass dayClass = DayClass.SUNDAY;
DayEnum dayEnum = DayEnum.SUNDAY;
System.out.print("dayClass "+dayClass.value+" \n dayEnum "+dayEnum);
}
}

Here SUNDAY, MONDAY are similar to static objects of Day if Day were a class.

We use enum as:
DayEnum day = DayEnum.SUNDAY;

enums are like constants. To simulate that, I have used value in DayClass. So every object of DayClass has an integer value associated with it.

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