newsservlet.java

JAVA Servlet2.3外文书籍源码

package personalPortal;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

/**
 * Title:        Professional Java Servlet Programming - Chapter 2
 * Description:  Servlet to output news to the client.
 * Copyright:    Copyright (c) 2001
 * Company:
 * @author Andrew Harbourne-Thomas
 * @version 1.0
 */

public class NewsServlet extends GenericServlet implements DataMapping {
  /**
   * Output a simple HTML news page
   *
   * @param request The object containing the client request
   * @param response The object used to send the response back
   */
  public void service(ServletRequest request, ServletResponse response)
    throws ServletException, IOException {
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();

    String count = (String)request.getAttribute(REQUEST_COUNT);

    out.println(getNewsPage(request));
    if (count != null) {
      out.println(getAccessData(count));
    }
  }

  /**
   * Returns the news page.  We include the request object as
   * parameter as normally we would personalise the content that
   * the client recieved, from a database or similar source.
   *
   * @param request - ServletRequest object
   * @return The news page
   */
  private StringBuffer getNewsPage(ServletRequest request) {
    StringBuffer news = new StringBuffer();
    news.append("<h2>The News Room</h2>");
    news.append("<p>Congratulations!</p>");
    news.append("<p>The news today. . . . . .</p>");
    return news;
  }

  /**
   * This returns the count of accesses to the site, formated in HTML
   *
   * @param count - indicates the number of site accesses
   * @return The formatted HTML page
   */
  private StringBuffer getAccessData(String count) {
    StringBuffer sbCount = new StringBuffer();
    sbCount.append("<br><p align=\"right\"><font size=\"-2\"");
    sbCount.append("color=\"darkred\">This site has been accessed ");
    sbCount.append(count);
    sbCount.append(" times.</font></p>");
    return sbCount;
  }
}