how to generate RSS for news sites programmatically in java/j2ee?

how to generate RSS for news sites programmatically? I dont k开发者_Go百科now how to start..

I learned how to write RSS from this article:

http://www.petefreitag.com/item/465.cfm

You can also just go to an RSS feed you like and press "View Source". Then you should simply use your java application to reproduce an XML similar to the XML you see (Only with your data).

When you finish, use one of many RSS Validators to validate your RSS.

It's easier than it first looks...

This code shows how to query a database to generate arbitrary XML from a JSP, manually.
It's not RSS, but the idea might be helpful to you.

private String ExecQueryGetXml(java.sql.PreparedStatement stmt, String rowEltName) {

  String result= "<none/>";
  String item;
  java.sql.ResultSet resultSet;
  java.sql.ResultSetMetaData metaData ;
  StringBuffer buf = new StringBuffer();
  int i;

  try {
    resultSet = stmt.executeQuery();
    metaData= resultSet.getMetaData();

    int numberOfColumns =  metaData.getColumnCount();
    String[] columnNames = new String[numberOfColumns];
    for( i = 0; i < numberOfColumns; i++) 
      columnNames[i] = metaData.getColumnLabel(i+1);

    try {
      //      if ((root!=null) && (!root.equals("")))
      //    buf.append('<').append(root).append('>').append('\n');

      // each row is an element, each field a sub-element
      while ( resultSet.next() ) {
        // open the row elt
        buf.append(' ').append('<').append(rowEltName).append(">\n");
        for( i= 0; i < numberOfColumns; i++) {
          item = resultSet.getString(i+1); 
          if(item==null)   continue;
          buf.append("  <").append(columnNames[i]).append('>');
          // check for CDATA required here? 
          buf.append(item);
          buf.append("</").append(columnNames[i]).append(">\n");
        }
        buf.append("\n </").append(rowEltName).append(">\n");
      }
      // conditionally close the row elt
      // if ((root!=null) && (!root.equals("")))
      // buf.append("</").append(root).append(">\n");
      result= buf.toString();
    } 
    catch(Exception e1) {
      System.err.print("\n\n----Exception (2): failed converting ResultSet to xml.\n");
      System.err.print(e1);
      result= "<error><message>Exception (2): " + e1.toString() + ". Failed converting ResultSet to xml.</message></error>\n";
    }
  }
  catch(Exception e2) {
    System.err.print("\n\n----Exception (3).\n");
    System.err.print("\n\n----query failed, or getMetaData failed.\n");
    System.err.print("\n\n---- Exc as string: \n" + e2);
    System.err.print("\n\n---- Exc via helper: \n" + 
                     dinoch.demo.ExceptionHelper.getStackTraceAsString(e2));

    result= "<error><message>Exception (3): " + e2 + ". query failed, or getMetaData() failed.</message></error>\n";
  }

  return result;
}

How about using a framework like Rome or jrss