Introduction to Java Servlets and JSP (1).ppt

C603.1 Design GUI using AWT and Swing .
C603.2 Develop program using event handling.
C603.3 Use network concepts (client/server, socket) in the
program.
C603.4 Develop program using JDBC connectivity to access data
from database and execute different queries to get
required result.
C603.5 Develop web based program using servlet and JSP
Course Outcomes of
Advanced Java Programming AJP (17625, C603)
Visit for more Learning Resources

Server-side Java for the web
 a servlet is a Java program which outputs an html
page; it is a server-side technology
browser
web server
HTTP Request
HTTP Response
Server-side Request
Response Header +
Html file
Java Servlet
Java Server Page
servlet container
(engine) - Tomcat

First java servlet
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class FirstServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException
{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<head>");
out.println("<title>First servlet</title>");
out.println("</head>");
out.println("<body>");
out.println("It works...<hr>");
out.println("</body>");
out.println("</html>");
}
}

What is a java servlet ?
 a java servlet is a java class extending HTTPServlet
class
 a java servlet class implements the doGet(), doPost()
or other equivalent HTTP method and (usually) prints
at the standard output an html file
 a java servlet class can contain any kind of java code
the JDK can compile
 a java servlet class needs to be compiled prior to using
it; it must use servlet-api.jar

Apache Tomcat
 the most well known servlet/jsp container
 is a web server + implementation of Java Servlet and
JSP (Java Server Pages) APIs
 is developed by Apache Software Foundation
 available at http://tomcat.apache.org/ under Apache
Software License

Installing Tomcat
1. Download the binary zip distribution (e.g. apache-
tomcat-6.0.20.zip) in a local folder (we will use c:temp
in the rest of the guide)
2. Set the environment variables
JAVA_HOME=path_to_JDK_installation_folder
CATALINA_HOME=path_to_tomcat_installation_folder
either as Windows system variables or in the files
startup.bat and shutdown.bat from the bin directory
Ex. place the following lines in the beginning of startup.bat
and shutdown.bat:
set JAVA_HOME=c:progra~1javajdk1.6.0
set CATALINA_HOME=c:tempapache-tomcat-6.0.20

Starting/shutting down Tomcat
 start Tomcat from a cmd prompter (window):
c:tempapache-tomcat-6.0.20binstartup.bat
 verify startup by pointing a browser to the url
http://localhost:8080
 shutting down Tomcat from a cmd prompter
(window):
c:tempapache-tomcat-6.0.20binshutdown.bat

Tomcat standard folders
 bin – contains executable files for controlling the server
(start, shut down etc.)
 conf – contains configuration files; most important
server.xml for configuring the server and web.xml a
general configuration file for web applications
 lib – libraries (jars) used by tomcat and deployed web
applications
 logs – log files
 temp – temporary files
 webapps – contains the web applications deployed
 work – contains files created by tomcat during running
(e.g. it crates a servlet from each jsp file)

Format of a web application
 web applications are stored in the webapps folder,
either as a folder or as a .war archive
 a web application (either a folder or a .war archive)
must contain the following files:
 WEB-INF folder
 WEB-INFweb.xml: a configuration file
 optionally the WEB-INF folder can contain the following
subfolders:
 classes: which contain servlets
 lib: which contains jars used by the web application
 html, jsp and resource files can be placed anywhere in
the web application home folder
 servlets must be placed in the folder or subfolders of
WEB-INFclasses

A very simple web.xml example
<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation=http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd version="2.5">
</web-app>

Configuring servlets
 for JSPs (Java Server Pages) no additional
configuration needs to be done
 for java servlets additional lines must be placed in the
web.xml file:
<servlet>
<servlet-name>ServletsName</servlet-name>
<servlet-class>The_Class_Name_of_the_Servlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name> ServletsName </servlet-name>
<url-pattern>/URL_of_the_servlet</url-pattern>
</servlet-mapping>

First JSP file
<html>
<body>
<%
out.println(“First JSP… It works<br/>");
%>
</body>
</html>

What is a Java Server Page (JSP)
 an html file containing parts of java code; the java code
is placed inside the “<% … %>” tags or some other
related tags
 Tomcat will create a servlet from the jsp file (which will
be saved in the work folder)
 when the jsp is requested the servlet is executed and
the output of the server is sent back to the client

Additional documentation
 for Servlets:
http://www.cs.ubbcluj.ro/~florin/PDPJ/ExempleSurseDocumentatii/07JavaServlet.pdf
 for JSP:
http://www.cs.ubbcluj.ro/~florin/PDPJ/ExempleSurseDocumentatii/08JavaServerPages.pdf
 examples of both:
http://www.cs.ubbcluj.ro/~forest/wp/JSP%20Servlet%20examples
For more detail contact us

Introduction to Java Servlets and JSP (1).ppt

More Related Content

Similar to Introduction to Java Servlets and JSP (1).ppt (20)

More from ansariparveen06 (20)

Recently uploaded (20)

Introduction to Java Servlets and JSP (1).ppt