Java EE 02-First Servlet

Introduction to
Java Enterprise
Edition

Configuring JBoss within Eclipse

Write your first Servlet

Fernando Gil
lobho.gil@gmail.com
Marzo 2012

Agenda


How to configure JBoss AS within Eclipse in
order to start the develop of JavaEE
applications.

We'll write our first Servlet class.

We'll discuss the deployment descriptor.

JBoss AS 6.1 & Eclipse Indigo

First download Eclipse IDE for Java Developers from:
http://www.eclipse.org/downloads and JBoss 6.1 from:
http://www.jboss.org/jbossas/downloads/

Open Eclipse.

Create a New Server:
Go to File/New/Other


Select Server Option


Search JBoss 6.x


Browse JBoss Home


Directory (the folder
where you saved
JBoss)
Click Finish


Important

If you can not find JBoss 6.x in the servers list,
try to Download additional server adapters:


Sometimes eclipse can
not find the JBoss
adapters, in that case
check this video tutorial
to solve the problem:
Eclipse & JBoss AS 6

Dynamic Web
Project


Open Eclipse and select File/New/
Dynamic Web Project

Set the Project Name and the
location

In Target Runtime we must select
the runtime of JBoss 6.x

The Dynamic web module version
will be set automatically

We can Click Finish

Creating our
Servlet

In order to keep the
example simple, we'll
create a servlet
selecting
File/New/Class and set
the values like in the
picture:

The Code
package com.dss.tut;

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

public class FirstServlet extends HttpServlet {
/* The service() method handles requests and creates responses.
* The servlet container automatically calls this method when
* it gets any request for this servlet.*/
public void service(HttpServletRequest req, HttpServletResponse resp)
throws IOException, ServletException{
PrintWriter pw = resp.getWriter();
pw.println("<html>");
pw.println(" <head></head>");
pw.println(" <body>");
pw.println(" <h1>Hello! this is my first
Servlet</h1>");
pw.println(" </body>");
pw.println("</html>");
}
}

Deployment Descriptor

We must indicate to the Application Server the configurations of our Servlets. The Deployment
descriptor is a XML file to accomplish this task. We will talk more about this file later. By the moment
we need to create a new file called web.xml in the directory: WebContent/WEB-INF of our project.

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
id="WebApp_ID" version="3.0">

<servlet>

<servlet-name>First</servlet-name>
<servlet-class>com.dss.tut.FirstServlet</servlet-class>
</servlet>
<servlet-mapping>

<servlet-name>First</servlet-name>
<url-pattern>/MyServlet</url-pattern>
</servlet-mapping>
</web-app>

Compilation and Deployment

Now we just need to select our project, right click, Run As.., Run on Server,
Select our JBoss Server and wait.

Remember the url pattern that we specified in the deployment descriptor,
because that is the way we'll access to the Servlet.

Next Lesson:
JPS Technology
Fernando Gil
lobho.gil@gmail.com
Marzo 2012

Java EE 02-First Servlet

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