Extracting atom feeds from URL sets

Question

I have a huge list of URL's and my task is to feed them to a java code which should spit out the atom contents. Is there an API library or how can I access them?I tried the below code but it does not show any output. I don't know what went wrong?

try {
URL url = new URL("https://www.google.com/search?hl=en&q=robbery&tbm=blg&
output=atom");
SyndFeedInput input = new SyndFeedInput();
SyndFeed feed = input.build(new XmlReader(url));
System.out.println("Feed Title: " + feed.getTitle());
for (SyndEntry entry : (List<SyndEntry>) feed.getEntries())
{
System.out.println("Title: " + entry.getTitle());
System.out.println("Unique Identifier: " + entry.getUri());
System.out.println("Updated Date: " + entry.getUpdatedDate());
for (SyndLinkImpl link : (List<SyndLinkImpl>) entry.getLinks())
{
System.out.println("Link: " + link.getHref());}           
for (SyndContentImpl content : (List<SyndContentImpl>) entry.getContents())
{
System.out.println("Content: " + content.getValue());
}

for (SyndCategoryImpl category : (List<SyndCategoryImpl>) entry.getCategories())
{
System.out.println("Category: " + category.getName());
}}}
catch (Exception ex) 
{
}

Answer 1

You can use Rome (http://rometools.org) to process atom feeds.

Answer 2

Every Atom feed have "feed" tag in it. So what you can do is read the url and check if it contains feed tag or not.

In java you can use inbuilt XMLparser library to do it -

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(url);
doc.getDocumentElement().normalize();

if (doc.getElementsByTagName("feed").getLength() > 0) {
       //do something
}