Tuesday, January 24, 2017

Spring MVC - Generate RSS Feed Example

The following example show how to generate RSS Feed using Spring Web MVC framework. To start with it, let us have working Eclipse IDE in place and follow the following steps to develop a Dynamic Form based Web Application using Spring Web Framework:

StepDescription
1Create a project with a name TestWeb under a package com.tutorialspoint as explained in the Spring MVC - Hello World Example chapter.
2Create a Java classes RSSMessage, RSSFeedViewer, and RSSController under the com.tutorialspoint package.
3Download Rome library Rome and its dependencies rome-utils, jdom and slf4j from same maven repository page. Put them in your CLASSPATH.
4Create a properties file messages.properties under src folder.
5The final step is to create the content of all the source and configuration files and export the application as explained below.
RSSMessage.java
package com.tutorialspoint;

import java.util.Date;

public class RSSMessage {
   String title;
   String url;
   String summary;
   Date createdDate;
   public String getTitle() {
      return title;
   }
   public void setTitle(String title) {
      this.title = title;
   }
   public String getUrl() {
      return url;
   }
   public void setUrl(String url) {
      this.url = url;
   }
   public String getSummary() {
      return summary;
   }
   public void setSummary(String summary) {
      this.summary = summary;
   }
   public Date getCreatedDate() {
      return createdDate;
   }
   public void setCreatedDate(Date createdDate) {
      this.createdDate = createdDate;
   } 
}
RSSFeedViewer.java
package com.tutorialspoint;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.view.feed.AbstractRssFeedView;

import com.rometools.rome.feed.rss.Channel;
import com.rometools.rome.feed.rss.Content;
import com.rometools.rome.feed.rss.Item;

public class RSSFeedViewer extends AbstractRssFeedView {

   @Override
   protected void buildFeedMetadata(Map<String, Object> model, Channel feed,
      HttpServletRequest request) {

      feed.setTitle("TutorialsPoint Dot Com");
      feed.setDescription("Java Tutorials and Examples");
      feed.setLink("http://www.tutorialspoint.com");

      super.buildFeedMetadata(model, feed, request);
   }

   @Override
   protected List<Item> buildFeedItems(Map<String, Object> model,
      HttpServletRequest request, HttpServletResponse response) throws Exception {
   
      List<RSSMessage> listContent = (List<RSSMessage>) model.get("feedContent");
      List<Item> items = new ArrayList<Item>(listContent.size());

      for(RSSMessage tempContent : listContent ){

         Item item = new Item();

         Content content = new Content();
         content.setValue(tempContent.getSummary());
         item.setContent(content);

         item.setTitle(tempContent.getTitle());
         item.setLink(tempContent.getUrl());
         item.setPubDate(tempContent.getCreatedDate());

         items.add(item);
      }

      return items;  
   }
}
RSSController.java
package com.tutorialspoint;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class RSSController {
   @RequestMapping(value="/rssfeed", method = RequestMethod.GET)
   public ModelAndView getFeedInRss() {

      List<RSSMessage> items = new ArrayList<RSSMessage>();

      RSSMessage content  = new RSSMessage();
      content.setTitle("Spring Tutorial");
      content.setUrl("http://www.tutorialspoint/spring");
      content.setSummary("Spring tutorial summary...");
      content.setCreatedDate(new Date());
      items.add(content);

      RSSMessage content2  = new RSSMessage();
      content2.setTitle("Spring MVC");
      content2.setUrl("http://www.tutorialspoint/springmvc");
      content2.setSummary("Spring MVC tutorial summary...");
      content2.setCreatedDate(new Date());
      items.add(content2);

      ModelAndView mav = new ModelAndView();
      mav.setViewName("rssViewer");
      mav.addObject("feedContent", items);

      return mav;
   }
}
TestWeb-servlet.xml
<beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:context="http://www.springframework.org/schema/context"   
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="
   http://www.springframework.org/schema/beans     
   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
   http://www.springframework.org/schema/context 
   http://www.springframework.org/schema/context/spring-context-3.0.xsd">
   <context:component-scan base-package="com.tutorialspoint" />

   <bean class="org.springframework.web.servlet.view.BeanNameViewResolver" />

   <bean id="rssViewer" class="com.tutorialspoint.RSSFeedViewer" />
</beans>
Here we've created a RSS feed POJO RSSMessage and a RSS Message Viewer which extends AbstractRssFeedView and overrides its method. In RSSController we've generated a sample RSS Feed.
Once you are done with creating source and configuration files, export your application. Right click on your application and use Export > WAR File option and save your TestWeb.war file in Tomcat's webapps folder.
Now start your Tomcat server and make sure you are able to access other web pages from webapps folder using a standard browser. Now try a URL http://localhost:8080/TestWeb/rssfeed and you should see the following result.
Spring RSS Generation

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