How to automate task in jsp?

Question

I want to create an sms messaging website using jsp. The sms i believe would be ez, i would just have to use sockets in a bean. However there is a specific functionality i want to implement where my website would send a dummy sms message every 5 minutes to the sms server just to test what speed that server is accepting messages at. This way i can display the server speed to users when the come to my site. My problem is i am not sure how to implement this functionality in jsp. It is a process that needs to happen like a new thread. It should happen whether or not people are visiting the website and it needs to happed every 5 minutes. I am wondering if this functionality could only be setup by my webserver or is there some way in jsp i could use a bean to do this.
Any assistance would be greatly appreciated

Answer 1

could the same thing be done with a jsp page instead of a servlet?The load on startup part, I'm not sure about. If you only wanted to wait til the first person hits a page, or just have a page that must be hit first on startup of the server to get the thread going, you could do that. But that requires direct user interaction to start things off....
As for examples....
In web.xml, you define a servlet and servlet mapping.
<servlet>
     <servlet-name>smsinit</servlet-name>
     <servlet-class>com.pckg.SMSInitServlet</servlet-class>
     <init-param>
          <param-name>config</param-name>
          <param-value>/WEB-INF/sms-config.xml</param-value>
     </init-param>
     <load-on-startup>2</load-on-startup>
</servlet>
<servlet-mapping>
     <servlet-name>smsinit</servlet-name>
     <url-pattern>sms.init</url-pattern>
</servlet-mapping>So that means that if the URL contains "sms.init", the smsinit servlet will be invoked. You probably don't need worry about that, if all you want is something that will load when the server starts. For that, that's what "load-on-startup" is for. The number value has to do with defining load order for multiple servlets. If left out, the servlet isn't initialized til the first time it's called via a URL. Otherwise, any number will do (for all practical purposes). The init-param config is useful if you need to define a file or some parameter that you can use on init to get some other information.
As for the servlet itself
package com.pckg;
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class SMSInitServlet extends HttpServlet {
     private ServletContext application = null;
     public void init(ServletConfig config) throws ServletException {
          super.init(config);
          application = config.getServletContext();
          String config = application.getInitParameter("config");
          File configFile = new File(application.getRealPath(config));
          // read the file or whatever....
          // start your thread class running and maybe put it in application
          // or pass the thread the application object which it could store
          // information in, or just have the thread use static methods/fields
          // or a singleton instance or something like that. 
          // the advantage to using the application scope is it limits it to being
          // accessed to JSP pages or other servlets within the web application only
     public void doGet(HttpServletRequest request, HttpServletResponse response)
                   throws ServletException, IOException {
          doPost(request, response);
     public void doPost(HttpServletRequest request, HttpServletResponse response)
                   throws ServletException, IOException {
          // do something here...  or nothing, if you want.
}