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Java Server and Servlet CS616 Team 9 Kim Doyle, Susan Kroha, Arunima Palchowdhury, Wei Xu
| Date post: | 22-Dec-2015 |
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Java Server and Servlet
CS616 Team 9
Kim Doyle, Susan Kroha,
Arunima Palchowdhury, Wei Xu
• History
• What is a Java Server/Servlet
• Architecture
• Pros and Cons
• Existing Java Servers
• Conclusion
Java Server and Servlet
History
• Web has undergone rapid changes
• E-Commerce Transition from static to dynamic environment Birth of Common Gateway Interface (CGI)
• CGI languages include Perl C, C++ Visual Basic Script
CGI Pros and Cons
Browser
HTTP
Web Server
CGI bin
Process
HTML
Database
•Insecure
•Platform dependent
•Inefficient
CGI vs. Servlet
• Servlet is Sun’s solution for CGI
• Both generate dynamic contents
• Servlet is light
• Servlet is secure
• Servlet is platform independent
• Servlet has better support for reusable component
Java Server Definition
• An instance of Java Virtual Machine
• One Java Server can support multiple concurrent services
• Java Server can start: administrative services HTTP services web proxy services
• Services are configured when server process is initiated
Java Servlet Definition
• Java class that runs in JVM associated with Server
• Java object that conforms to a specific interface defined by the server architecture
• Loaded and invoked by services
• Multithreading
• Extends the functionality of the server
Server and Servlet Interaction
Browser
HTTP
Web Server
Servlet Engine
Servlets
HTML
Database
Application
Business Log.
Demo and Servlet Life Cycle
Application Server
Servlet Engine
Init()
Service ()doGet ()
doPost ()
Destroy()
Do… ()
link to Utopia
HttpResponse
HttpRequest
PrintWriter
link to Laptop
Simple Sample (Hello World)
import java.io.*;import javax.servlet.*;import javax.servlet.http.*; public class HelloWorld extends HttpServlet { public void doGet(HttpServletRequest request,
HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("<html><head><title>"); out.println("Hello World!</title>"); out.println("</head><body>"); out.println("<h1>Hello World!</h1>"); out.println("</body></html>");
}}
Servlet Functions
• Reads data sent by user
• Looks up information from HTTP request
• Connects to database
• Invokes legacy application
• Executes RMI or CORBA calls
• Executes algorithm
• Formats document
• Sends document back to clients
Servlets
Algorithm
JDBC
PANDA
Project Group Assignment Servlets in Action
Tomcat
HTTP
Link to Laptoplink to Utopia
Servlet with Synchronization…
public class AlgorithmRequest extends HttpServlet {public void doPost (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
PrintWriter output; response.setContentType("text/html"); output = response.getWriter();
if(getConnection()){ String SemesterCourse =
request.getParameter("SEMESTERCOURSE"); synchronized (this) { AlgorithmControl ac = new
AlgorithmControl(SemesterCourse); …………………………………………
Servlet Advantanges
• Convenient
• Efficient (light weight thread, memory)
• Inexpensive
• Keep intellectual properties on the server
• Portable
• Powerful
• Secure
Server Advantanges
• Efficient Memory management Light weight
• Platform independent
• Thread-safe
Server Considerations
• Java is slower than C++
• However, Java server uses threads
• WebSphere from IBM
• WebLogic from BEA
• 9i Application Server from Oracle
• Jrun from Allaire
• iPlanet from Sun
• Tomcat from Apache
Java Servers or Engines
Apache and Tomcat
• Industrial strength Web server
• Tomcat is a servlet engine that can be plugged in with Apache
• Apache and Tomcat can be down loaded from http://jakarta.apache.org
• FREE!
Servlet vs. PHP
• PHP also free open source
• PHP consists of tags in HTML document
• Servlet is more widely supported
• Servlet is written in Java with extensive API for: database access distributed objects networking
Servlet vs. ASP
• ASP is a competing technology from Microsoft
• Servlet is portable to other operating systems web servers
• Servlet is more powerful for complex applications
• Better support for reusable components
Conclusion
• Java server and servlet are Economical Portable Powerful Secure
Thank You
