Accessing Beans From A Servlet; Quick Introduction To Servlets; Retrieving A Home Interface And Creating A Bean - Red Hat APPLICATION SERVER - JONAS Tutorial

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Manual (296 pages)

Table Of Contents

Table of Contents

8.1. Quick Introduction to Servlets

According to Java Servlet Programming, 2nd Edition—O'Reilly

A servlet is a generic server extension—a Java class that can be loaded dynamically to expand the func-

tionality of a server. Servlets are commonly used with web servers, where they can take the place of CGI

scripts.

Servlets are executed inside a Java Virtual Machine. The ofﬁcial reference implementation and most

commonly used servlet container is Apache's Tomcat Server, which is packaged with Red Hat Appli-

cation Server and is also freely available from the Apache web site http://jakarta.apache.org.

Servlet/JSP engines are embedded in J2EE

8.2. Retrieving a Home Interface and Creating a Bean

Here is an example on how to retrieve the home interface of a bean named Region from a Servlet and

then create a new instance of this bean:

import java.io.*;

import javax.naming.Context;

import javax.naming.InitialContext;

import javax.rmi.PortableRemoteObject;

import javax.servlet.*;

import javax.servlet.http.*;

public class RegionServlet extends HttpServlet

{

/**

* Called on a GET request for this servlet

* @param request a

* @param response a

* @exception IOException if an error occurs

* @exception ServletException if an error occurs

public void doGet(HttpServletRequest request,

HttpServletResponse response) throws IOException, ServletException

{

private PrintWriter out;

response.setContentType("text/html");

try

{

out = reponse.getWriter();

}

catch (IOException ioe)

{

ioe.printStackTrace();

}

out.println("